The JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag used to close all associated processes when the job terminates is not supported in Windows 2000.
Probably the best we can do is to remove 'subprocess' closing support for win2k.
I'll preface this by saying this subject is a bit beyond my capabilities, but I did find reference to TerminateJobObject(HANDLE hJob, UINT uExitCode) on http://www.microsoft.com/msj/0399/jobkernelobj/jobkernelobj.aspx
Since it appears the zabbix code (execute.c line 376) includes this call, I think the JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag would be safe to omit under win2k, but the functionality of closing associated processes would remain.
Yes, thats right. Actually in this case setting JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE
is not really needed. So the only thing that remains is setting JOB_OBJECT_LIMIT_BREAKAWAY_OK
flag (which is preventing child processes to explicitly disassociate themselves from the job),
though I'm not sure it's event set by default - need to verify.
Fixed in development branch svn://svn.zabbix.com/branches/dev/ZBX-6140$
I've compiled the Windows agent and tested it on a Windows 2000 system. I've confirmed this resolves the reported issue. Am I allowed to mark the issue as tested so it can be merged upstream?
no, there is also supposed to be a full code review 
Successfully tested!
Fixed in:
pre-2.0.5rc1 r33379
pre-2.1.0 r33380