MasterRig not opening, "serious error"

Just joined the forum. I have Wavelab Elements 9 and I just updated to 9.1 and now MasterRig and a few of the other Steinberg plugs won’t open. I get the “Serious error, Wavelab could control it but it is recommended you save your work and reopen Wavelab” message. I’m on Windows 7 64 bit. It happened a while back and I went back to version 9.0, but I thought I’d give it a try again.