Ok, sliced the 24mm cube to test my printer and it worked just fine. Next I wanted to print a knob for the lcd and I get error:

Can't call method "clone" on unblessed refrence . . . Print.pm line 157.

So I went back and tried to slice the same 24mm cube I sliced last night and now get the same error. Any idea what this is? I googled it but everything I looked at said to upgrade Slic3r but the build guide says not to update Slic3r.