Afaik the plugin is basically the same code as Qlikview Desktop, but just running in the browser as an activex component. It will need much more ram to work than the ajax client does. If at all possible I suggest you let your users access the documents using the ajax client. You may need to add more ram to your server too if you have more files of that size and more than a handful of users. See this document and this discussion.
either change to the Ajax client or consider a special Terminal Server, where clients could remotely login, which would be a 64bit environment.
Of course, there will be additional costs with the Terminal Server solution, like Windows license, hardware, etc.
I don't see a different solution, if your clients are stuck at x86 and you cannot reduce the memory amount for the given reports.
Thx both of you for valuable input. I did what you advised me and changed the setup so this report could be opened only with ajax client.
Now the page is reconnecting to the server and after the reload its unselected (appx. after 120 sec). I changed the possible calc time on mngm console to 240 sec. but it didnt help.
In the mean time I will try other browsers just to be sure its not an ie setting.