My suggestion would be to clear the local cache.
Preferences > Media & Disk Cache > Empty Disk Cache
I think the "Zanzibar error" is related to mocha shape masks. As far as I know it has been fixed in the latest CC2018 Update (After Effects 15.0.1). Have you checked that you have the latest version installed?
I don't have any mocha stuff in these projects at all. I tried emptying the disc cache, but the projects still crash and give the error. Again, importing these projects into a new project seems to be ok. Just kind of a hassle to constantly nest projects in new ones....
I figured it out. It's the Suitcase Fusion plug-in. I uninstalled that and projects that previously crashed now work again. . .
Strangely it doesn't do it to every project. I will let the font software people know. Guess it is not AE issue,
delete application.xml file