use vars %::FILENAME;
--- cut ---
if (!defined($::FORM{'data'})) {
print qq{
        <TABLE ALIGN=center><TR><TD ALIGN=left>
<FORM METHOD=post name=maindata ENCTYPE="multipart/form-data">
        <INPUT TYPE=hidden NAME=id value=$id>
            To attach a file to <A HREF="show_bug.cgi?id=$id">bug $id</A>, place it in a
            file on your local machine, and enter the path to that file here:<BR>
        <INPUT TYPE=\"file\" NAME=\"data\" SIZE= 60 >
        <P>
            Please also provide a one-line description of this attachment:<BR>
        <INPUT NAME=description VALUE="$::FORM{'description'}" SIZE= 60 ><BR>
            What kind of file is this?
        <BR><INPUT TYPE=radio NAME=type VALUE="patch">Patch file (text/plain, diffs, etc.)
        <BR><INPUT TYPE=radio NAME=type VALUE="text/plain">Plain text (text/plain, tracebacks, syslog output, bios messages, kernel oops, etc.)
        <BR><INPUT TYPE=radio NAME=type VALUE="text/html">HTML source (text/html)
        <BR><INPUT TYPE=radio NAME=type VALUE="image/gif">GIF Image (image/gif)
        <BR><INPUT TYPE=radio NAME=type VALUE="image/jpeg">JPEG Image (image/jpeg)
        <BR><INPUT TYPE=radio NAME=type VALUE="image/png">PNG Image (image/png)
        <BR><INPUT TYPE=radio NAME=type VALUE="application/octet-stream">Binary file (application/octet-stream)
        <BR><INPUT TYPE=radio NAME=type VALUE="other">Other (enter mime type: <INPUT NAME=othertype size= 30 >)
        <P>
    <CENTER><INPUT TYPE=submit VALUE="Submit"></CENTER>
</FORM>
</TD></TR></TABLE>
<P>
};
} else {
    if ($::FORM{'data'} eq "" || !defined $::FORM{'data'}) {
        Punt("No file was provided, or it was empty.");
    }
    my $desc = trim($::FORM{'description'});
    if ($desc eq "") {
        Punt("You must provide a description of your attachment.");
    }
    my $ispatch =  0 ;
    my $mimetype = $::FORM{'type'};
    if (!defined $mimetype) {
        Punt("You must select which kind of file you have.");
    }
    $mimetype = trim($mimetype);
    if ($mimetype eq "patch") {
        $mimetype = "text/plain";
        $ispatch =  1 ;
    }
    if ($mimetype eq "other") {
        $mimetype = $::FORM{'othertype'};
    }
    if ($mimetype !~ m@^(\w|-)+/(\w|-)+$@) {
        Punt("You must select a legal mime type.  '<tt>$mimetype</tt>' simply will not do.");
    }
--- cut ---

# В оригинале имя файла как бы получается тут $::FILENAME{'data'};, но оно undef