Error 500 with following rewrite rules

gistfile1.txt

<system.webServer>
  <rewrite>
    <rules>
      <rule name="Rewrite PHP" stopProcessing="true">
  		  <match url="(.*)" />
			  	<conditions logicalGrouping="MatchAll">
						<add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
						<add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
						<add input="{REQUEST_FILENAME}" negate="true" pattern="(.*).php" />
			  	</conditions>
			  <action type="Rewrite" url="{R:1}.php" />
      </rule>
    </rules>
  </rewrite> 
</system.webServer>