Sunspots. Or evil gnomes. One of the two. Probably gnomes.

Without seeing the code there's any number of things that it could be doing, from calling sleep( 5+rand(5) ) to traversing the current working directory and posting a copy of your secret muffin recipe to USENET. When you use module; the code is pulled in and any statements outside subroutine declarations get executed (remember use is effectively inside a BEGIN { } block), so there's no telling what the problem is without more info.

(And another thing: modules starting with lower case names are bad ideas as by convention those are "reserved" for pragmatic modules for Perl's use (e.g. strict or base); granted this particular name isn't likely to cause a conflict but it's bad style.)

Update: Changed phrasing in the parenthetical comment on naming to make it read more good.