I recently ran across an issue in an environment where packages were no longer getting installed on the Distribution points.
We were getting the error "ERROR ExecMethod(): Failed to execute AppCreate2. error = The service cannot be started, either because it is disabled or because it has no enabled devices associated with it."
After looking through changes that were submitted we found that a recent request was submitted to disable the Service "Com+ System Application". Once this was renabled, we received another error: "ERROR ExecMethod(): Failed to execute AppCreate2. error = COM+ was unable to talk to the Microsoft Distributed Transaction Coordinator".
Sure enough we looked at the Distributed Transaction Coordinator service and it was set to Disabled as well, we re-enabled the service and the packages quickly processed.
Hope this helps someone trying to troubleshoot this error message.