So, this Perl script should draw a rainbow - http://theducks.org/gdtest.txt

But it doesn't, it gets to the end of the red -> yellow transition and dies ( see http://theducks.org/gdtest3.cgi ). So you'd think, my loop/if/elsif isn't working correctly.. but when you print the values, they're correct..

Any ideas?

I have a feeling this has bitten me before, and it's memory related, but now I'm not so sure..