If a package gets stuck in the "Install Retrying" state at a BITS-enabled ditribution point.
And you see the following error message logged in the Microsoft Configuration Manager\Logs\distmgr.log on the server:
"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."
It might be because of the "COM+ System Application" service is set to anything other then automatic startup. It may be set by a group policy or it could have been set manually.
More info can be found here: http://support.microsoft.com/kb/917485