If it's one of these "I am not a bot"-like bot detection thingies, you might need some mouse interaction. Luckily, Perl got you covered.

Last year, i wrote a post on how to write an Autoclicker: Autoclicker! Cheating is winning, too!

Maybe all you need is to automate your browser, then grab the file from your Browsers download folder.

Or if you are after some data within the page, you could just make the script move the mouse pointer to the beginning of it, hold down left mouse button and move the pointer to the end (depending on the data, a double-click might also mark it). Then press CTRL and C, and voila, the requested data is in your clipboard. Perl got cou covered there, too: Clipboard