You should be connecting from CenterED client to CenterEd server, not RunUO. And the CenterED server should be there where your mul files are (or create a separate copy of your muls and place server's .exe there).
Here's an example of cedserver.ini (the file that defines CenteED config, should be placed at the same folder with cedserver.exe):
Code:
[Config]
Version=2
[Network]
Port=2597
[Paths]
map=D:\Games\UOml\map0.mul
statics=D:\Games\UOml\statics0.mul
staidx=D:\Games\UOml\staidx0.mul
tiledata=D:\Games\UOml\tiledata.mul
radarcol=D:\Games\UOml\radarcol.mul
[Parameters]
Width=768
Height=512
[Accounts]
alrick=255:b25892cf26f2b6af2fa9ad473ccf25:357
Almost forgot: you should create an account for yourself, because it's not possible to just write passwords into .ini file - they are encrypted as you see.
And here's what I've managed to do with CenterED (took about 15 minutes):
Farmer's house (undecorated yet):

Basement:
