Thank you for your post.
Your post has me a little confused, so let me verify I have the right information.
1. You created a Runtime solution, and the database file has the extension .BB7 Correct?
2. You are able to copy the database file to the Windows 2003 Server where FileMaker Server is located. Correct?
3. In the Admin Console, you are able to open the database file with the .BB7 extension. Correct?
4. On your original machine, you still have the file with the .BB7 extension. Correct?
5. Launching the Runtime solution, you get a message that the .BB7 cannot be found. Correct?
What machine is the Runtime Solution being launched? What is the OS of the local machine?
Any other information you can provide may be helpful.