Products sometimes disappeared

Hello, I've got the same problem: sometimes, during the site navigation, clicking on the categories all the related products disappear. :cry:
I've tried to reset the master to categories id in the admin control panel, but nothing was solved. Some minutes ago the problem has come back again, I'm using Firefox; Probably it sounds stupid, I wanted to to open the same location with safari and camino, with these all works while in the same time FF doesn't show any product yet! (I attached 2 jpg to demonstrate this)... Maybe there's a bug due to sessions?
The site url is https://quasar335.webfactional.com/test/dangerouswork/trunk/ but I doubt it can be an help to look the problem, because the products desappear sometimes, in a random time, or in a precise time when something is triggered but I don't know what. The site is hosted by Webfaction.
Anybody can help me to solve the problem? :lookaroun
Thanks in advance,
Piero

That may be a host problem. I could be wrong, but ask your host if there are any issues known on the server that would cause this.

I haven't had that problem with mine at all and I've been actively selling for a while.

JP