Cannot spawn a child process from within a cluster worker in Node v0.6.18+

node_cluster_child_process.js

/*

$ uname -a
Linux coderuler 3.2.0-24-generic #39-Ubuntu SMP Mon May 21 16:52:17 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
$ node -v
v0.6.18
$ echo "console.log('foobar'); process.exit(0);" > foo.js
$ node node_cluster_child_process.js 
child stderr > 

child stderr > cluster.js:215
  process.send(msg);
          ^

child stderr > TypeError: Object #<EventEmitter> has no method 'send'
    at queryMaster (cluster.js:215:11)
    at EventEmitter._startWorker (cluster.js:184:3)
    at startup (node.js:91:17)
    at node.js:551:3

Child process exited with code 11
Worker exiting
Master exiting

*/

var cluster = require('cluster');

if (cluster.isMaster) {
  cluster.fork();

  cluster.on('death', function() {
  	console.error('Master exiting');
  	process.exit(0);
  });
}
else {
  var child_process = require('child_process');

  var args = ['foo.js'];
  // uncomment to show that the problem seems to arise only when
  // attempting to access the file system:
  //args = ['-e','console.log("barbaz"); process.exit(0);'];
  
  var ch = child_process.spawn('node', args);

  ch.stdout.on('data', function(data) {
  	console.log('child stdout > ' + data.toString());
  });

  ch.stderr.on('data', function(data) {
    console.log('child stderr > ' + data.toString());
  });

  ch.on('exit', function(code) {
  	console.error('Child process exited with code ' + code);
  	console.error('Worker exiting');
  	process.exit(code);
  });
}

how to fix that?

nodejs v0.8 fixed this bug.