The object was "http://jesin.tk/("
Yes my blog URL with a bracket
I've thorougly checked my blog code and nothing was found related to this. A look into the access logs showed this
126.96.36.199 - - [22/Jun/2011:09:19:31 -0500] "HEAD /( HTTP/1.0" 404 - "" "\"Mozilla/4.0 (compatible; MSIE 6.0; Windows 98; Win 9x 4.90)\""
I have the following plugins installed
Google Analytics for WordPress
Google XML Sitemaps
W3 Total Cache
WP Category Posts