PSA - Expense Management

Hi there, We are running Expense Management on production since a couple of month now. We are using Lawson 9.0 Portal with Finance/HR Application 8.1. Windows 2003 IIS and Webshere 6.0.2.17 are running for the Portal and W3k3 IIS is use for expense management. There is single sign-on setup between portal and PSA. Using this configuration, our end users pass thru the portal to access everything (Finance applications and Expense Management) Problems happen to some end users only when they try to access expense management program. The error message come from IE with 'Cannot open the internet site' If the same user click again on the link, the error don't happen until they clear IE cache. After investigation with several IE versions, connection type (Wan, Lan, VPN). We found that in some case, the very first time my end users click on the link they receive an uncompleted java program usually stored in the temporally IE file.( This file content link with the IIS server name and a session ID). The second time they click, those files are download completely and the error message do not happen. We are free until he clears IE cache, after that he needs to click 2 times to get in. Something very strange, this kind of situation do not happen when a computer is not on the domain! If I use the same computer, remove it from the domain, the error do not happen. If some of you already resolve this issue, or if you have a work around you are welcome Stephane