Could be a lot of things....
First off, what zones?
Second.. What version of the emulator are you running, 070-xxx?
How did you install it? Did you use Cavedudes package?
If you did, did you enter ALL of the SQL updates that were in the changelog.txt file that came with the emulator version that you downloaded?
^^^^ Is VERY important that you got ALL of them!
Lastly, what kind of computer are you running it on, processor, memory...?