Testing is exactly what I'm doing. The old server will keep running until the new Zentyal is ready for production, but the ongoing beta phase gives me time to test and prepare our software environment for 3.0 and Ubuntu 12.04, and at the same time I can help Zentyal developers by locating bugs. I find it hard to believe that Zentyal LDAP would change radically during beta, as the essential bits have remained the same since early eBox versions.
I may have found the problem; On the old server it's possible to do LDAP searches anonymously, but this is not the case with the new one, so I guess Apache tries to perform an anonymous LDAP operation, when instead it should try to bind using the remote user's uid and password.
I could set AuthLDAPBindDN and AuthLDAPBindPassword in .htaccess, but I don't like the idea of passwords laying all over my system.
Another alternative would be to allow anynymous searches on the new server too, but I'd like to keep security as tight as possible.
Any help or suggestions would be greatly appreciated.