I'm pretty new to the Nook having just got it today, but I did some reading prior to attempting anything to see how easily I could back out if I had to.
Have you tried basically starting over (ie. Let go of the multi-boot dream for a bit and get back to basics)
You know, take a SD card, use diskimager to put the clockwork 18.104.22.168 image on it with the CM7 full ROM and boot to that, then format system, data and cache with clockwork and finally install the CM7 zip image (and gapps I guess) just to get going again.
If it all works, maybe take another run at whatever you are trying to do with the multi-boot stuff.
Network: Family Mobile (T-Mobile)
Current Devices:Galaxy Note 8.0 , Galaxy Nexus GSM/HSPA+, Kindle Touch
Other/Family Devices: Samsung Galaxy S II, iPhone 3GS, iPad 2
Previous Phones: Evo 3D, Epic 4G, , Evo 4G, Samsung Vibrant, Samsung Intercept, T-Mo G1
Previous Tablets:Galaxy Note 10.1, Nexus 7, Galaxy Tab 8.9, Kindle Fire, Dell Streak 7, Asus Transformer, iPad, Archos 101, Nook Color and aPad