There are two versions of the Lexar Memory Stick reader: A and B.
The B version is built as a 'USB Mass Storage Device", and will mount without any drivers in OS X.
The A version requires a special driver to work. A driver was written for OS 9, but never for OS X, despite over 18 months of promises
Yours is a revision 'A', your only recourses are
(1) use it in Classic (if you have Classic), with an OS 9 file manager like File Buddy.
(2) Get what you can for it on eBay and try again.
(3) Call up Lexar and b!tch at them until they trade your A for B. Good luck with this approach.
Does the Camcorder have a USB port in addition to the Firewire port?