When Working with AppFabric you may receive receive error message if some of your Applications (Services) use custom elements like for example custom service behavior or similar.
This is the error:
"Unrecognized element '<name of the custom element>' "
For this error and many other there is a Patch KB980423, which is not contained in the RTW.
Here is a patch: http://support.microsoft.com/kb/980423
Jun 11 2010, 10:51