First and most important hint: Call perl with the -w parameter. On Unix you just have a first line "#!/usr/bin/perl -w" which does that automatically, with ActiveState Perl or whatever you are using on windows you might have to use perl /w <scriptname> on the command shell, I don't know how it works there.

This will tell you that you have defined $table and $format twice (with my). Not a problem and not an error, but it leads to errors later when you want to use the first $format value and get only the second $format.

It will also tell you that $FIELDLENGTH is undefined. The error message is "Use of uninitialized value in concatenation (.) or string at ./t4.pl line XX" with XX the line in which you print $FIELDLENGTH. So you never put anything into that variable

Another hint: chomp() can be used to delete CR/LF line endings from a string. Much easier than substr(...) and works on unix too (where there is only one character, CR, as a line ending).