Hi,
What module you are using to show Virtuemart products on your homepage? Tell me the exact name of the module.
Also install Firebug (it is a plugin for Firefox) and check the Console logs against jQuery Conflict issue. See if you are seeing any RED WARNING. This might be a jQuery conflict issue (for example, the conflict might be caused by the jQuery based slideshow you use on homepage. I don't know.)
If you provide me your website URL, i can check and guide you to solve it.
Regards,
Support