[otrs] OTRS and IE 6

Hi all, are there any know problems between IE 6 and OTRS 2.2.6. Some of our customers have the problem that they have to do several attempts to navigate through their customer webinterface, because they get a "side can not be loaded" error page of internet explorer. With firefox we don't get this error. But the customers can't use firefox. 2 other users of he same customer don't have this problem with the webinterface but use the same system configuration and version of IE 6. Can anybody please explain me what the problem is, and how I can solve it!? Kind regards Thorsten