You aren't saying whether you are using this module within another module for inheritance, or just to have objects of that type, nor are you saying how you are calling set_items. If you give the minimum amount of code to trigger the error, someone might be able to help. But right now, the best we can say is "check line 13 of that other file!". That's just as likely to be useful as anything else anyone could say.

-- Randal L. Schwartz, Perl hacker