... if it's a regular old perl program then the problem probably has to do with some kind of interpolation ambiguity. See the multi-arg usage of system and it might just solve the problem (eg, system "sh", $script_name, @other_arguments). You shouldn't need to call "sh," but it certainly doesn't hurt anything either.

UPDATE: I deleted some of this post because kyle is correct and I missed that return value reversal completely.