I then tried --debugmsg +reg to see what it was sensing, but then the familiar old race condition reared its ugly head: "Error Number: 0x80040706 Description: Object reference not set Setup will now terminate"
This is normally generated by InstallShield... why do you say it's a race condition?
Because it comes and goes depending on how much --debugmsg logging I select. Could be some other kind of bug, too, I just jumped to a conclusion.
I had this problem with InstallShield, but it seems to work if you run it with -dll ole32,oleaut32,rpcrt4=n