I have a dir called foo, and in that I have lib and bin. The scripts in bin need stuff in lib. I do someth
foo
lib
bin
Parse out the complete path to your .pl via __FILE__ and and tack the ../lib on the end or pop off the last element of split(/\//,__FILE__) and add /lib to that.
.pl
__FILE__
../lib
split(/\//,__FILE__)
/lib