I suppose it's a problem produced by your Gavick template. If I search for something with "Firebug" enabled in my Firefox browser, it tells me "$Gavick is not defined
Line 480". Also that template (and I guess your K2) are loading several additional javascript files including two more different versions of jquery, which are likely to produce conflicts when using VirtueMart.
You can try if it helps to disable 'Using the Virtuemart jQuery' in VM2 Configuration - Templates.
If it doesn't solve your problem, I would recommend to try another template for comparision, i.e. the free "ShopLab" template.
From what I frequently see in the forum, I think it generally is a good idea to avoid templates which use their own framework. They often load a lot of things conflicting with VM2.