You won't be able to download ipfilter.dat using a regular wget. Apparently, the server checks referer and what agent is downloading the file.

Solution: Make your wget request look and act like a regular browser.

#!/bin/bash
# NOTE: change "user1" to the user's directory name OR where the ipfilter.dat file resides

cd /home/user1/.azureus
wget -N --referer="http://voxel.dl.sourceforge.net/sourceforge/emulepawcio/ipfilter.dat" \
-U "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.7) Gecko/2009021910 Firefox/3.0.7" \
http://voxel.dl.sourceforge.net/sourceforge/emulepawcio/ipfilter.dat