http://urlquery.net/report.php?id=8941150
http://zulu.zscaler.com/submission/show/545708d1694280d45529fc90a3e10d44-1390461506

If you believe your site is free of any malicious code, you can request avast to allow it through the contact form:
http://www.avast.com/contact-form.php

My advise:
Get your own (dedicated) server.