When i hit connect it first tries to connect to my NAT address (192.168.178.100) and 2 or 3 seconds later it then tries to connect to the internal NAT address of the VPN Provoider. I only can connect, if i switch off my vpn (which i dont want to… 
Any suggestions? =)
@JAMy sounds like strange behaviour. What is the IP address or hostname you are putting into the ThinLinc client?