Un-finalized means that there's no "lead-out" on the disc, which makes it an unreadable file system on a PC.
There are disc rescue programs around that might pull the files off the disc. Look at ISOBuster and similar software. You might also look at your options for closing the discs, some burning applications can do this.
If you still have the Panasonic, just close the discs. If you want a solution for moving video around without the hassle of closing the disc, consider DVD-RAM.