Do you run your scripts as script.pl or as perl script.pl ?
Does it make any difference if you run system("dir <nul"); ?
Does perl -V produce normal output ?

You probably should give us a copy'n'paste of an actual script that demonstrates the problem ... along with a copy'n'paste of the output. (I think it's highly likely that you know what you're doing ... but the only way *we* can actually *know* that you're not doing something silly is if you give us a copy'n'paste of input and output.)

Cheers,
Rob