Can you describe in detail how you've set up:
- Your relationship for the conditional value list
- The specific settings on your field that you've formatted with this value list.
You might also consider uploading a copy of your file to a file share site and posting a link to the file here so we can examine the file directly.
There's a knowledge base article on conditional value lists you may also want to check out: http://help.filemaker.com/app/answers/detail/a_id/5833/kw/conditional%20value%20list