Given that you say it worked, but now does not, and that you have tried a full reinstall and it still does not work you go back to the usual question *what changed*. You have almost certainly added something that is causing this issue, either a Win2k SP or Hotfix or an update to HP Service Desk.

The fact that a simple .bat file executing shell commands does not work either really isolates it in the Java VM or HPSD software. I suppose there is a 1% chance it could be hardware so if a machine is available I would set up W2kS, Perl, and HPSD on another box an see if the issue is gone as a sanity check.