Seems that step master>Build Necessary>Build VS Version?VSVersion=cmake>Action Parallel>Action Execute Tests>CppUnit Config Parallel>CppUnit Test Config?Config=Release&Plat=Win32>CppUnit Test Run>CppUnit Excute Parallel>CppUnit Excute Targets Parallel?CppTestTarget=CppUnit is a parallel step, and execution of some child step failed. Are you able to find more information from failed child steps?

Actually, this is the strange thing: There are child steps that fail with same error, but in there there is nothing that fails.

20:13:44,907 ERROR - Step 'master>Build Necessary>Build VS Version?VSVersion=cmake>Action Parallel>Action Execute Tests>CppUnit Config Parallel>CppUnit Test Config?Config=Release&Plat=Win32>CppUnit Test Run>CppUnit Excute Parallel>CppUnit Excute Targets Parallel?CppTestTarget=CppUnit' is failed.
java.lang.RuntimeException: Error executing step process job.
at com.pmease.quickbuild.stepsupport.StepProcessTask.reduce(StepProcessTask.java:126)
at com.pmease.quickbuild.stepsupport.StepProcessTask.reduce(StepProcessTask.java:19)
at com.pmease.quickbuild.grid.GridTaskFuture.get(GridTaskFuture.java:178)
at com.pmease.quickbuild.grid.GridTaskFuture.get(GridTaskFuture.java:182)
at com.pmease.quickbuild.stepsupport.ParallelStep.triggerChildren(ParallelStep.java:83)
at com.pmease.quickbuild.stepsupport.CompositeStep.run(CompositeStep.java:133)
at com.pmease.quickbuild.stepsupport.Step.doExecute(Step.java:680)
at com.pmease.quickbuild.stepsupport.Step.execute(Step.java:577)
at com.pmease.quickbuild.stepsupport.StepExecutionJob.executeStepAwareJob(StepExecutionJob.java:36)
at com.pmease.quickbuild.stepsupport.StepAwareJob.executeBuildAwareJob(StepAwareJob.java:60)
at com.pmease.quickbuild.BuildAwareJob.execute(BuildAwareJob.java:77)
at com.pmease.quickbuild.grid.GridJob.run(GridJob.java:149)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: java.lang.OutOfMemoryError: Java heap space

The only unusual thing is, the withing this later parallel step, there is one step that has been skipped for no obvious reason.
But I have other parallel steps where sub-steps are being skipped (intentionally) and those do not fail.
I could send you the complete build log if needed.

One thing I noted looking at the server log is, that during this build, another node has triggered it's build, but on another agent though.
This failing build runs on the server.

So wrapper.java.maxmemory=4096 is on server? This might be a bit small if you have many steps running on server, please bump to 8192 to see if it makes any difference.