We run a cron triggered CVS-Request for 80 of our projects. All request configured to run every 6 hours.

On most of this projects hudson exit with a failure.

[workspace] $ cvs -q -z3 update -PdC -r branch-1_5 -D "Sunday, September 5, 2010 7:03:39 PM UTC"
java.io.IOException: Cannot run program "cvs" (in directory "/home/hudson/hudson-data/jobs/..."): java.io.IOException: error=12, Cannot allocate memory
at java.lang.ProcessBuilder.start(ProcessBuilder.java:460)
at hudson.Proc$LocalProc.<init>(Proc.java:192)
at hudson.Proc$LocalProc.<init>(Proc.java:164)
at hudson.Launcher$LocalLauncher.launch(Launcher.java:638)
at hudson.Launcher$ProcStarter.start(Launcher.java:273)
at hudson.Launcher$ProcStarter.join(Launcher.java:280)
at hudson.scm.CVSSCM.run(CVSSCM.java:981)
at hudson.scm.CVSSCM.update(CVSSCM.java:544)
at hudson.scm.CVSSCM.checkout(CVSSCM.java:362)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1038)
at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:479)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:411)
at hudson.model.Run.run(Run.java:1258)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:318)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:129)
Caused by: java.io.IOException: java.io.IOException: error=12, Cannot allocate memory
at java.lang.UNIXProcess.<init>(UNIXProcess.java:148)
at java.lang.ProcessImpl.start(ProcessImpl.java:65)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:453)
... 15 more

Is it possible to limit the number of simultaneous execution for an external programm?