With newer versions of FileMaker, you can use Manage Exteral data sources to see and update any external file references that need to be updated after your move.
One of the serious shortcomings older versions of FileMaker such as version 5 is that you had no direct access to the file references. Often, you had to open the database with a full access password and then manually locate and open files each time Filemaker tried to find and open a different file and was unable to find the other file. You could have numerouse references to the same file so sometimes it felt like bopping gophers with a shovel--you'd fix a reference to file A only to have a different script or layout use a different reference to the same file A--popping up the file not found message all over again.
One "fix" that minized some of this is to have a script set to run on file open that opens all the other files. That allowed many of your file references to find and open files even if they had been moved and you only needed to update the references in this one script.