Some months ago I have fixed a similar error opening WMP for Vista (fully updated with SP2):
I found solution here:
"The file wmploc.dll has a version number of 11.0.6000.XXXX where 11.0.6000.XXXX was expected. Windows Media Player is not installed properly and must be reinstalled. Do you want to install the Player from Microsoft Web site?"
Windows Media Player 11 for Vista
Deleting in particular only this entry related to wmploc:
I hope to help anyone has tried to solve this issue.