If you have imported your elements as "standard import", Director looks, by default, at the same relative location it was stored on the hard drive. This means that if you have a directory structure of convenience while creating the project, you must maintain that structure on the Final distribution.....
If your dir files are stored in something like -
D:\clientA\mydirproject\mydirectorfile.dir
then the final projector will, by default, look down the directory tree on the CD to find any associated files.
CDDRIVELETTER:\clientA\mydirproject\movies\mymovie.mpg
The answer?
1. If it is not too confusing (too many associated movie files), I keep them all in the root directory with the dir files.
2. Right before distribution, I copy only (and all) files required by the projector to a "top level" directory (i.e. - D:\distribution)
3. Burn the master on the CD with NO sub-directories (all files are located in the root directory of the CD) or at the very most, the exe file in the root and the video files one directory under it.
The "proper" distribution convention is to have the exact same relative addresses to all external files on the CD as you do on your hard drive...
Bottom line?
Make the "dir" working directory a top-level directory and keep the same relative path to your movies on the CD as on your hard drive.
Don't worry about the drive letter, that will not matter when you burn the CD....also, remember any xtras you used must be on the CD in a directory called xtras, located one under the root director of the CD.
Hope this helps,
Crispy