If you're doing it in FileMaker client on a Mac, you can try File->Import->Folder..., since you have the ability to just import the file names into a text field, one record per file. I think it treats PDF files as "images", so if you point it to the directory and only import the names, that should do the trick.
It's a while since I've done it, but I used this for a similar purpose.
Thanks Rob I was totally overthinking that one... suppose i needed pdf editing tools that might include cropping, rotating etc.?
If you're on Mac, the built in Preview program can handle all of those.