Change
<plugin name="poweradminurt" priority="19" config="@b3/extplugins/conf/poweradminurt.xml"/>
To
<plugin name="poweradminurt" config="@b3/extplugins/conf/poweradminurt.xml"/>
and move it up after the punkbuster plugin line, being careful to retain the xml format.
You might want to download a copy of Notepad ++ as your text editor seems to do funny things with line breaks. This should also warn you if you have messed up the xml formatting.