If you get an error during the uninstall, remove the following line of code from the C:\Inetpub\wwwroot\wss\VirtualDirectories\<port>\web.config SharePoint file where "<port>" is the port that web site runs under on the server.
<add name="JivePageController" type="Jive.SharePoint.Services.HttpModules.JiveSharePointHttpModule,Jive.SharePoint.Services,Version=1.0.0.0,Culture=neutral,PublicKeyToken=9df0a1232f502088" />
If you find this line in the web.config file, and you can't find the Jive.SharePoint.Services.dll in the Global Assembly Cache (C:\Windows\Assembly), SharePoint will be unaccessible for that web application