Hi there.
Here's what can lead to the problem. When your application gets upgraded, app's uninstaller usually unregisters the application, which tells UltiDev Cassini server to unload the app and release the IP port the app was bound to. The problem you've reported may be caused by one of two possibilities.
1. Attempting to register an application on the port that is already taken by another. This may happen if you run upgrade installation of your application, and uninstaller failed to unregister the previous version of application. To verify if this is the case, go to http://locahost:7756/ to see which applications are registered. If you see two instances of your application is being registered there on the same port, please let us know - we will help you straighten out your custom installer steps.
2. Sometime, even when app registration steps are written properly, this problem pops up on slow machines: either on old, low-memory boxes, or on virtual machines under MS Virtual Server and VmWare Server. As far as we can tell, this is the timing issue: when Cassini applications configuration changes, Cassini unloads all applications and releases IP ports, and then loads new configuration and proceeds to loading applications. The problem is that sometimes, even though applications are unloaded, IP port does not get released quick enough for the following re-loading of apps to grab the same port again. If this problem occurs rarely, then the workaround could be as simple as rebooting the machine where server runs. If this is impossible for any reason, another workaround would be to stop the Cassini service programmatically before registering the application, and the restarting it again. This can be done either using ServiceController class from .NET Framework, or by using net stop, net start command line. If you decide to go this route, please let us know - we'll provide more information on how to do this all.
Best regards,
UltiDev Team.
Please donate at
http://www.ultidev.com/products/Donate.aspx to help us improve our products.