If you had previously installed Windows Server AppFabric 1.0 (WSA 1.0) the update to v 1.1 can fail. Before you start the installation of WSA 1.1 be sure that the Task Scheduler does not contain the task with the name “Consolidator”.
If this task does exist, remove it and then start the installation.
Read the complete post at http://developers.de/blogs/damir_dobric/archive/2012/01/16/windows-server-appfabric-v1-1-setup-issue.aspx