SharePoint Timer Service not starting up

I recently discovered that on one of my farms my SharePoint Timer Service would continuously start up and crash.
There are numerous entries like the following 2 in the System log:

The SharePoint 2010 Timer service terminated unexpectedly.  It has done this 2965 time(s).  The following corrective action will be taken in 30000 milliseconds: Restart the service.

and

The timer service could not initialize its configuration, please check the configuration database.  Will retry later.

The following is found in ULS:

SPTimerStore.InitializeTimer: SPConfigurationDatabase.RefreshCache returned SPConstants.InvalidRowVersion

and

The timer service could not initialize its configuration, please check the configuration database.  Will retry later.

I verified that my service's user context had the correct username and password.

I also cleared the timer cache (and, yes, I emptied the GUID folder and instead of deleting it).

There were a couple of DCOM 10016 errors which seemed irrelevant to this issue, but I fixed those anyway (as per http://sajiviswam.wordpress.com/2011/04/15/the-machine-default-permission-settings-do-not-grant-local-activation-permission-for-the-com-server-application-with-clsid-000c101c-0000-0000-c000-000000000046-sharepoint-2010/)

I'm still getting the same problem.

I started looking at the Fusion log as described in http://soerennielsen.wordpress.com/2009/01/14/fixing-the-timer-service-when-everything-breaks-down/ but think I'm in too deep.

What's curious is that the Timer Service stopped functioning around the time the web application was extended in order to support HTTPS and there are some new files in C:\windows\assembly\GAC_MSIL. However, I am unable to make any connection. As far as I can tell, my assemblies in the GAC are not corrupted since all other functions appear to be working.