Need to click twise to come previous page in firfox 2.0 in my web site why that???

My web site need to support FF version 2.0 we have a issue with the back button where for each page visited, it adds an additional history item(in to back button history list), what would be the cause of this this issue does not occure in the later versions of FF or any other browser. is this is a known issue with FF 2.0 or is it that we need to update some config file to handle this ??? == This happened == Not sure how often == User Agent == Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; MS-RTC LM 8; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)