play California karaoke DVD with folksfun software

I'm trying to play the California karaoke DVD with folksfun software. I followed instruction on author website
Q: What does "3rd Party DB" means?
 A: folksKJ support third party DB (California Electronics). If you are the owner of the DVD put it in your drive.
    Rename the file "ce.db" to "external.db".
    Go to Settings->Songs and set the path of the 3rd Party DB to the location of your HOTDOG00.DAT file.

But when I clicked on "3rd Party DB", it says "Invalid File Name"?  Does anyone know what I'm doing wrong?
Or do you guys know any other software to play this kind of DVD. Thankssss...