Bad Virus alert

Please perform Avast Free.
In my website www.ffdesign.pl Avast found a troyan.

you have a SPAM:SEO infection

Sucuri report. http://sitecheck.sucuri.net/results/www.ffdesign.pl/
malware info. http://labs.sucuri.net/db/malware/malware-entry-mwspamseo

similar to this. http://forum.avast.com/index.php?topic=135198.0