This is a very common problem. I agree with aragorn that it is far better to correct this at the source rather than fix the symptoms. I can't see your code, so my recommendations have to be rather generic.

First, debug from the command line, not through the CGI interface.

Second, stick in some warnings before doing any string concatenations or interpolations, i.e. something like:

if (not $variable) { warn "\$variable is uninitialized\n"; }
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This should help you isolate which variables are empty.

Why are they empty? One common reason is that you have forgotten about empty lines in the input data. I like next if /^\s+$/; to deal with those common cases.

Also, I think you should leave strictures, warnings and taint checking ON even in production code. If it is properly written, it should not generate warnings.

--
Regards,
Helgi Briem
helgi AT decode DOT is