LaserSoft Imaging

I downloaded, installed and initialized SFE-6.0.2r10 (Expr1680) and had problems with lock up on Scan.
Now I have downloaded SFE-6.0.2r15(Expr1680) and I can scan OK in Demo mode but am unable to enter the serial number sucessfully. Do I need another serial number to enter for this revision?
Also, is this version compatible with any other Epson scanner - e.g. Epson 1660 ? or do I need another version of Silverfast 6?

Mac OS 9.2
Photoshop 6

Dear Murray,
your SilverFast(Expr1680) version is ONLY compatible to this very device. Do NOT use it in combination with a 1660 model.