You need, at a minimum to to replace these three lines:

require("cgi-lib.pl")
print &PrintHeader;
&ReadParse(*form_data);
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with:

use CGI;
print CGI::header();
my %form_data = CGI::Vars;
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But I'm not sure I'm doing you a favor by telling you that. You really should start by learning something about perl and CGI. Just copying scripts and code snippets is likely to get you into trouble.