OK, now that we know what version you're running, go ahead and add these things at the top of your programs for the time being:

use strict;        #  Helps to prevent a few common coding            
+     
                   #  "mistakes"

use warnings;      #  Turns on "lexically-scoped" warnings, 
                   #  a bit better than -w

use diagnostics;   #  Makes error messages more helpful
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If I had known about Diagnostics from the beginning, I would have saved myself so much work... ;)

Update: Fixed improper capitalization as pointed out by the nice AM.