Just had serious fun with a failing install of OCS SE.
Ended up being service account passwords that had a space in them.
WOW. You gotta be kidding me.
There are a variety of hotfix and QFE and updates that purportedly fix this, but how the fsck are you supposed to get that stuff in place when the silly thing won't even finish the install?
AAR, changed the passwords and now we are good.