Your

_DATA_
^    ^
[download]

really confuses the issue... and will not compile (is not a token which Perl knows how to interpret).

If, in the first pseudocode snippet, you're trying to use http://www.domain.com/path/to/RSS/feed.xml and http://www.domain.com/path/to/second/RSS/feed.xml, then the header for that data must be:

__DATA__
^^    ^^
[download]

But since your second code example appears to try to obtain the URLs from outside this script, using CGI, there is no point to a __DATA__ section. Try using almut's solution.

In that case, however, you're going to have to use CGI in the second snippet... and have a source (a form in an html page, most likely) from which to obtain your URLs.