Heads up if you use XenDesktop 5 or XenApp 6.
If you get the error “An error occurred while making the requested connection” when trying to connect through web interface running Xendesktop 5 or XenApp 6 the issue could be a Microsoft patch. We just ran into this issue with XenDesktop 5.
This is the patch http://support.microsoft.com/kb/2286198 that wreaks havoc.
Here is a forum article related to the issue http://forums.citrix.com/thread.jspa?threadID=271745&start=15&tstart=0
You will also get the following errors or similar in the event log
Log Name: Application
Source: Citrix Web Interface
Date: 9/30/2010 8:49:17 AM
Event ID: 30024
Task Category: None
Site path: C:inetpubwwwrootCitrixAG5.
The XML document sent by the Citrix servers could not be processed because it contains invalid XML. This message was reported from the XML Service at addresshttp://localhost:80/scripts/wpnbr.dll [com.citrix.xml.NFuseProtocol.RequestLaunchRef]. The specified Citrix XML Service could not be contacted and has been temporarily removed from the list of active services. [Unique Log ID: e28daedd]