I scanned some old prints (about 20) and stored the files as TIFFs from Photoshop CS2 (Windows). I am trying to use Bridge (Windows) to keyword them. When trying to add keywords to about 6-8 of them, I get the above error message. Oddly, others do not cause the error.
#1
Try opening the files in question and then resaving them and closing. It's possible that Bridge can only store certain types of metadata in files saved in an Adobe product, which adds the needed hooks for XMP metadata. There are loads of different ways a TIFF file can be constructed, including use of proprietary tags pointing to data areas that will be used only with a particular program.
#2
Are these files on a hard drive? If they're not and are on a disc, you will not be able to write to or save the XMP file. Move the files to your hard drive and try again.
#3