If I had no idea whatsoever, I would write a quick test:

#!/path/to/perl
print join ", " , @INC;
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Usually you need admin privileges on the machine to install modules into the directories that perl normally searches (except for the cwd). If this is a one-off thing (and you don't taint check), I would create the proper directories relative to the dir the script it in and drop the .pm file in there.