Thanks for the reply toolic
The PDFLib you suggested from CPAN is different from what I'm using. http://pdflib.com/
I apologize for putting up the whole code. The place where I'm getting the error is

my $font = $pdfInstance->load_font("Helvetica", "winansi", "");
if ($font == 0)
{
    print LOGFILE ("\nERROR in creating font instance:", $pdfInstance-
+>get_errmsg());
    print "\nERROR in creating font instance\n\n";
}
[download]

Both the Print statements are printing out the custom error message I typed (i.e.,ERROR in creating font instance).
But the exception message coming from $pdfInstance->get_errmsg() is empty. Previously I got the file not found exception for pdflib.upr, which I fixed by using the resourcefile parameter available in pdflib. I added the font location in the upr file I mentioned above. But yet the code is failing.
The system I'm working on is AIX. I'm not sure whether the 'Helvetica' font is available in that environment. Could this be a reason?

Thanks