If your environment is restricting how much memory you can have, you might be able to inspect and change this with ulimit, but my guess would be that you're simply exhausting physical memory.

You can measure the size of Perl data structures at run time with Devel::Size.

You can use something like DBM::Deep to write a large hash to disk instead of holding it in memory.

If you're building a large Excel spreadsheet in memory (which it sounds as if you are), I don't know how to help that (besides just having more memory). In that case, at least Devel::Size will be able to tell you.