Who ever you are, if you can not help you should just shut up, and why waste your time writing such useless words!!!

You misunderstand the purpose of perlmonks

You said It works if only two /T and /V is inside of the /Fields, the question is why it doesn't work with all of them., indicating, that the problem, as far as IE is concerned, is the format of the PDF file

Your job is to verify the format of the PDF file

Oops, I did it again, I said PDF -- it doesn't matter, PDF/FDF -- the format of either of these files is not perl

If your perl program is not generating the FDF file correctly, we can help you fix your perl program

If firefox opens the FDF file without problem, then that means your perl program is generating the FDF file correctly

So there is nothing we can do to help you, short of installing the same version of windows, internet explorer, fdf software you have, and trying out your program

Do you think it is reasonable for someone to install windows/IE/FDF just to debug your problem?

If you think the problem is HTTP related, try these Tutorials: CGI Help Guide, Troubleshooting Perl CGI scripts