I vaguely remember something similar :)
system returns a status code, you're not grabbing it. My guess is that you're probably not using a complete path. Try passing parameters as if they are parameters:

$status = system("command","param1","param1");
[download]

or if you don't need the status code, just the return values, you could consider qx()

Greetz
Beatnik
... Quidquid perl dictum sit, altum viditur.