Perl 5.004, huh? I think your problem is related to your perl version. So it can be that ${link} will always give a problem with a perl this old. Note that link is a built-in function.

To get around your problem, I'd suggest using sprintf or printf. In particular, the first line, with the sub call, will look a lot cleaner:

my $link = sprintf '<a href="%s">', getQueryString('title'); 
printf "<th>%sTitle</a></th>\n", $link;
[download]

or something even more compacted.

p.s. you should really reconsider properly escaping these strings, for proper inclusion in HTML. The proper order is first URL-escaping, and next HTML-escaping the string. Perhaps you have already taken care of it, or part of it, in your sub, and I don't know what subs you have available for this purpose (it depends on the library you use), so I won't give the complete code.