If your app is indeed opening a server port, there's not a lot you can do about it. Any given port can only be opened by a single handler per machine. Really the client app should open an outgoing connection on port 139 to connect to the server, not the other way round. You can have as many outgoing (client) port connections as you like. Is this app certified for Citrix? -----Original Message----- From: Carlos Sanabria [mailto:csanabria@xxxxxxx] Sent: 24 November 2003 22:48 To: thin@xxxxxxxxxxxxx Subject: [THIN] App problem with multiple users So I've run into a dead-end problem... we're trying to publish Aloha POS ( http://www.alohapos.com <http://www.alohapos.com/> ) through Citrix and everything was going fine till we tested for multiple users running the app. Problem is, APPARENTLY the client application sets up port 139 so the server can communicate with it anytime it needs to. So evidently the first instance of the app loads, but just as a second user tries to launch the app she gets the error "Cannot register station. 0xD", I'm guessing because port 139 is already taken, but it is still a wild guess. If that is the case, I ran out of ideas to work around this problem, so any help would REALLY be appreciated. Thanks a lot, Carlos Sanabria, MCSA, CCA IT Consultant