What do you have on your website that links to vlaze?

Did this occur on a specific page of your forum? Or is it occurring everywhere on your forum?
Does the same thing happen to you when you visit any other freesmfhosting.com websites?

The more info you can give me, the better.

I just can't spot vlaze on the main page of your forum either.

I don't think its related to your forum at all.   Put Chrome bak on here,  does not happpen to me after going all over the forum.    So I did a bunch of research and it appears you more then likely have a trojan that has effected your system and your browser.    If your virus program is not up to date do so and run a complete scan.  

Malwarebytes Anti Malware
Superantispyware
Download, Install and update them.  Then go offline, run them in Safe Mode.

It "might" be related to virtumunde ..  you can try running this fix (do the other stuff first)
http://vundofix.atribune.org/

Also go to this site and do an online scan:
http://support.f-secure.com/enu/home/ols.shtml
And this one:
http://housecall.trendmicro.com/housecall/start_corp.asp
and this one too:
http://www.pandasoftware.com/activescan

Not knowing for sure which one you may have (there are a couple causing an issue and vlaze is mentioned in them as well as showing up in hijackthis logs)  I know it seems like a lot to do but cover all bases.

Might be a good idea after doing all of that to download hijackthis and post the log at a site where someone can go over it and advise you..    could do that at the following site but be sure to follow their rules on where/how to do so
http://www.spywareinfoforum.com/index.php?showtopic=79038

A couple of other thoughts on this.   It could be a false positive.    Chrome is new and there are some issues being reported about it, as well as some very valid security issues with it. 

Early Security Issues Tarnish Google's Chrome

At first I thought it could be it was hitting on one of the flash ads as they can show alerts for some programs but I noticed you are ad free.   

You said you did a scan with Avg.  Just in case its not a false positive I would also grab the Malwarebytes download and run it, scan your pc with it.   As I said,   I put Chrome back on my computer adn went all over your forum, clicked links all over the place,   went everywhere possible and I never got an alert.   If nothing else its a good program as is SuperAntispyware.  Unfortunately the net is a very different place then it was many years ago and keeping the junk off is very important now.