style caching problem

[samergains]

Hi everyone..

I'm facing a problem that i'm not sure how to fix it. here is a description about it:
after we moved our forum to a new server, sometimes the style is loosing some of it's css settings. that happens only on two pages: on home page and on user profile page.
all what it takes to fix it is to clear the browser cache and refresh the page. but it happens again with time. ( i attached 2 screenshots, one is when the problem happens, the second one is after clearing browser cache and which is the normal style of the forum).
i use vb4.2 and here is link to our forum: http://arabic.rt.com/forum/
any ideas what could coz such a problem?

thanks in advance for any help.