I wrote a danbooru downloading script for Python 2.7.3 for those interested. It's not totally complete yet (you'll have to modify the script for the settings rather than have the ability to use command line options right now) but it's an alternative to using the Perl script.
As of now it only supports Danbooru. It was more of a personal use thing, so the coding isn't very good, but I thought I might as well share it in case I'm not the only one who can't get anything done in Perl. If anyone ends up being interested in extra features I can probably add them.
Python 2.7.3 here (doesn't work on 3.x): http://python.org/download/
Script here: http://pastebin.com/1rY4KzcL
Copy and paste into an empty file with the .py extension, open in Notepad or similar to change your username, password, tags and directory to download to, and run. For the downloading part it works similarly to the Perl script.
Updated