Well, I can confirm that it's possible to use UNC paths, but there are restrictions. The 8.3 limit can be on all separate parts of the path... I'm not really sure. I've used it to print (write using fwrite()) to networked printers in a NT network, and that worked just fine (\\BOB\HPlaser).
I'm afraid it won't go for database files, for that GrafxSoft is correct I'm afraid.
Just go for a drive-mapping and you won't have much problems.
HTH
TonHu