Well based on your less than enligtening description:

1. If you are on Win32 get used to it, this is SOP. Attend to your 3 finger salute.
2. If you are on *nix I suggest not slurping the entire contents of your file system into a scalar. This leads to memory exhaustion and data is then swapped to disk. This is bad, as it means you have yet more info to read
3. fork while 1 is bad

Seriously how on earth do you expect anyone to offer any sort or sensible suggestion based on your 'invisible code that does script like stuff does not work under stress crashing computers (plural?) on unspecified operating system using some version of some scripting language, presumably perl' description?

I would suggest Tutorials and some of the how to ask a question links as the first stop. Then I would suggest posting a snippet of code that recreates you does not work issue here.

High on the list is using all your memory and hitting swap.