Getting close :-). Now the error message is:
^[^[zentara@zentara:~/1down > ./n-color-puzzle unknown color name "" at /usr/lib/perl5/site_perl/5.6.0/i586-linux/Tk/Widget.pm line 196. at ./n-color-puzzle line 106 It's still about $bgcolor. So I just added it manually.

eval{($bgcolor,$boardcolor,..............................
$_+=0 for $size,$cols,$rows;

$bgcolor= $bgcolor||"lightgrey";

END{nstore ;........................................
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Nice game!!! I really like the ability to play with a photo. This is top-notch stuff. :-)