Forgive me but I am having a hard time understanding the Perl question here. Sounds like you should schedule a .bat file that deals with the error return values. There is only one "0" value, so that was picked as success (normally). If that doesn't describe what you have, then have a cli program (.bat file) deal with it and schedule that. Or am I missing something obvious?

Oops:

print "WARNING: scheduled task [$key] finished with error [$va
+lue]\n";
[download]

Perhaps this is where you put some special case exclusion code that ignore certain error codes($value) from certain programs($key)?