Hi there!
This might be an issue with your CPU/GPU strength, since after you log in you'll get the character selection menu and it will literally transfer you from one place to another on the map when you select your character. It might be the first mentioned issue or it might be an unstable game in itself. If you have any modifications done the old school way (Overwriting files with an IMG editor) or similar. If you could check your game directory and see if you can clean it as much as possible so it's basically factory new, it might work. If not, feel free to comment again on this topic and I'm sure one of the REAL tech guru's playing/working on the server would be glad to help you out!