I had this problem with Firefox (click logout and redir to admin). Try deleting your blog’s cookie. That took care of the issue for me.
Just to add, delete the plugin from your wp-content/plugins directory or you *will* get a fatal error after you upgrade to 1.5.1
My wp-rss2.php and wp-atom.php validated, but wp-rss.php did not. I received the XML error described above. My (simplistic?) solution was to change line 31 of wp-rss.php (based partly on http://mosquito.ww.wp.xz.cn/view.php?id=1132 ) from
<description><?php the_content_rss('', 0, '', get_settings('rss_excerpt_length')) ?></description>
to
<description><![CDATA[<?php the_content_rss('', 0, '', get_settings('rss_excerpt_length')) ?>]]></description>
Maybe I’m naive, but it just looks like this was missed in the orig. Hope this helps and if I’m totally wrong, let me know.
