If you use #!c:\Perl\bin\perl.exe -w as your shebang line, you may very well get errors when running CGI under a webserver, at least, I've found it to do that from time to time.

You'll find that (to my knowledge) all Windows boxes run perl the same regardless of where you point the shebang line, but with a few different compilers (like ActivePerl), it will take the -w to give you warnings. If that doesn't work, you should utilize the use warnings; line.

Hope that helps.