When you add multiple groups or members in AD you use ';' to sepperate them.
When you use ';' to sepperate the DNS suffixes in the GPO your computer will have problems with DNS resolving. The correct format for DNS suffixes is "CSV", so you have to use ',' to sepperate your DNS suffixes.
If you have used ';' like i did, you will see that when you try to ping, the computer automatically adds a dot '.' at the end of the hostname. It does this also when resolving RDN's, making it impossible to resolve. This problems isn't salvagable when it occurs, because the registry shows the correct vallue's (HLKM\CurrentControlSet\Services\TcpIp\Parameters).
Restoring the system state however seems to be the only sollution.