You need this driver: http://light.dnsprotect.com/~blld/spca3050/spca3050a_driver.zip
Be sure to backup A, B drives as well as firmware and all numbers from "RSV info" before you do any modifications. Also know that these RSV parameters might change unexpectedly erasing/invalidating all content you have saved on the flash. RSV is something like partition table.
The "good stuff" isn't in Default.fw, it's in AIMG.
AIMG and BIMG are normal fat partitions which can be mounted under linux with "mount -o loop AIMG /media/foo". I don't think you can do this with windows.
Nero or some other program specialized in cdrom images and the like might be able to open these.
VirtualBox + damn small linux might be a good combo for this also.
Once mounted, you can find the "good stuff" in .bin files at root folder.
It is my belief that this kind of firmware upgrade can be used to de-brick devices. (I messed up the RSV once and got it back by reflashing).
On some devices you might also need to bring you device to a special state that allows firmware updates.
In this mode you should not see any picture from the screen.
On my device identical to uxcell cyclone (http://www.dealextreme.com/details.dx/sku.10238),
I found a hidden button at the line in connector.
This device is based on spca3052a.
I'd think spca3050a and spca3052a are mostly compatible.