CommaFeed error during Maven build

error.log

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building CommaFeed 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.4.1:clean (default-clean) @ commafeed ---
[INFO] 
[INFO] --- gmaven-plugin:1.5:execute (default) @ commafeed ---
[INFO] 
[INFO] --- maven-processor-plugin:2.2.3:process (process) @ commafeed ---
[INFO] 
[INFO] --- maven-resources-plugin:2.5:resources (default-resources) @ commafeed ---
[debug] execute contextualize
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 32 resources
[INFO] Copying 10 resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ commafeed ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 123 source files to /home/user/tmp/commafeed/target/classes
[INFO] 
[INFO] --- wro4j-maven-plugin:1.6.3:run (default) @ commafeed ---
[INFO] Executing the mojo: 
[INFO] Wro4j Model path: /home/user/tmp/commafeed/src/main/webapp/WEB-INF/wro.xml
[INFO] targetGroups: all
[INFO] minimize: true
[INFO] ignoreMissingResources: true
[INFO] destinationFolder: /home/user/tmp/commafeed/target/commafeed/static
[INFO] jsDestinationFolder: null
[INFO] cssDestinationFolder: null
[INFO] groupNameMappingFile: null
[INFO] wroManagerFactory class: ro.isdc.wro.maven.plugin.manager.factory.ConfigurableWroManagerFactory
[INFO] The following groups will be processed: [all]
[INFO] folder: /home/user/tmp/commafeed/target/commafeed/static
[INFO] processing group: all.css
LoadError: no such file to load -- rubygems
  require at org/jruby/RubyKernel.java:1062
   (root) at <script>:1
org.jruby.embed.EvalFailedException: (LoadError) no such file to load -- rubygems
	at org.jruby.embed.internal.EmbedEvalUnitImpl.run(EmbedEvalUnitImpl.java:136)
	at org.jruby.embed.jsr223.JRubyEngine.eval(JRubyEngine.java:90)
	at org.jruby.embed.jsr223.JRubyEngine.eval(JRubyEngine.java:153)
	at ro.isdc.wro.extensions.processor.support.sass.RubySassEngine.process(RubySassEngine.java:69)
	at ro.isdc.wro.extensions.processor.css.RubySassCssProcessor.process(RubySassCssProcessor.java:50)
	at com.commafeed.frontend.resources.SassOnlyProcessor.process(SassOnlyProcessor.java:22)
	at ro.isdc.wro.model.resource.processor.decorator.ProcessorDecorator.process(ProcessorDecorator.java:87)
	at ro.isdc.wro.model.resource.processor.decorator.ProcessorDecorator.process(ProcessorDecorator.java:87)
	at ro.isdc.wro.model.resource.processor.decorator.ProcessorDecorator.process(ProcessorDecorator.java:87)
	at ro.isdc.wro.model.resource.processor.decorator.SupportAwareProcessorDecorator.process(SupportAwareProcessorDecorator.java:39)
	at ro.isdc.wro.model.resource.processor.decorator.ProcessorDecorator.process(ProcessorDecorator.java:87)
	at ro.isdc.wro.model.resource.processor.decorator.ExceptionHandlingProcessorDecorator.process(ExceptionHandlingProcessorDecorator.java:56)
	at ro.isdc.wro.model.resource.processor.decorator.ProcessorDecorator.process(ProcessorDecorator.java:87)
	at ro.isdc.wro.model.resource.processor.decorator.BenchmarkProcessorDecorator.process(BenchmarkProcessorDecorator.java:44)
	at ro.isdc.wro.model.resource.processor.decorator.ProcessorDecorator.process(ProcessorDecorator.java:87)
	at ro.isdc.wro.model.group.processor.PreProcessorExecutor.applyPreProcessors(PreProcessorExecutor.java:213)
	at ro.isdc.wro.model.group.processor.PreProcessorExecutor.processAndMerge(PreProcessorExecutor.java:104)
	at ro.isdc.wro.model.group.processor.PreProcessorExecutor.processAndMerge(PreProcessorExecutor.java:78)
	at ro.isdc.wro.model.group.processor.GroupsProcessor.process(GroupsProcessor.java:84)
	at ro.isdc.wro.cache.support.DefaultSynchronizedCacheStrategyDecorator.loadValue(DefaultSynchronizedCacheStrategyDecorator.java:90)
	at ro.isdc.wro.cache.support.DefaultSynchronizedCacheStrategyDecorator.loadValue(DefaultSynchronizedCacheStrategyDecorator.java:36)
	at ro.isdc.wro.cache.support.AbstractSynchronizedCacheStrategyDecorator.get(AbstractSynchronizedCacheStrategyDecorator.java:57)
	at ro.isdc.wro.manager.ResourceBundleProcessor.serveProcessedBundle(ResourceBundleProcessor.java:66)
	at ro.isdc.wro.manager.WroManager.process(WroManager.java:152)
	at ro.isdc.wro.maven.plugin.Wro4jMojo.processGroup(Wro4jMojo.java:230)
	at ro.isdc.wro.maven.plugin.Wro4jMojo.doExecute(Wro4jMojo.java:132)
	at ro.isdc.wro.maven.plugin.AbstractWro4jMojo.execute(AbstractWro4jMojo.java:132)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
	at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
Caused by: org.jruby.exceptions.RaiseException: (LoadError) no such file to load -- rubygems
0    ERROR ExceptionHandlingProcessorDecorator - Failed to process the resource: ro.isdc.wro.model.resource.Resource@61cace42[CSS,/sass/app.scss,true] using processor: com.commafeed.frontend.resources.SassOnlyProcessor@25d4cd60. Reason: org.jruby.exceptions.RaiseException: (LoadError) no such file to load -- rubygems
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 21.519s
[INFO] Finished at: Sat Jun 29 16:27:16 BST 2013
[INFO] Final Memory: 40M/290M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal ro.isdc.wro4j:wro4j-maven-plugin:1.6.3:run (default) on project commafeed: Exception occured while processing: org.jruby.exceptions.RaiseException: (LoadError) no such file to load -- rubygems -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException