If a texture map link is broken in formZ, the Resource Manager will attempt to find it in the search paths you have specified. Note that texture maps will often display properly in formZ even if the filepath is broken, because the bitmap image is cached within the formZ project. It is possible that your filepath is broken, and that the Resource Manager is finding another file with an identical file name within the search paths you have specified. In general, if you are going to use the Resource Manager, avoid duplicate file names within the search path space.
If you wish, you can opt to not search for anything using the Resource Manager-- just delete the search paths. Or you can temporarily disable any or all search paths by clicking in the "use" column ( a plus sign indicates that the location will be searched). Also, you might temporarily disable the search paths, run a render and see what paths formZ is missing (again, consult the Project Log), and then re-link them, in Material Parameters.
We have not received your Project Log yet. It is likely that we can determine the cause from the log, and let you know how you might avoid the issue in the future. You can also check the log yourself to determine what formZ texture locations may be missing, and which files have been located in alternate locations and re-linked.
Resource Manager documentation: