Updated last night after reading this and came along with optimism this morning only to find I still have the same error message :-(. Looks like I'll have to see if I can still rollback to get a backup this month.
Can't rollback, too late.
Changed my admin settings to replace trusted installer with me, now listed as an admin; still have access denied. Very much cross at not being able to do a back-up without needing to swing through hoops and waste a lot of time. My DOS days are long behind me.