It would not surprise me at all. The DOS function used by DISKSPACE() in FPD returned a signed, 32 bit integer for free space; this meant that >2GB of free space came back as a negative number, and a number >4GB would overflow a 32 bit value entirely, wrapping around. Is it an issue with the return from DISKSPACE(), or specific commands failing to work. I've successfully used FPD apps across a LAN on very large NetWare, NTFS and FAT32 volumes shared through the network in the past.

What specific symptoms are you seeing?