Not been something that I've tried. Does the regular music library work off the share??
I wonder if it's a permissions issue. If regular music library doesn't work - check what account your GBPVR Recording Service is running under. If "LocalSystem" you'll probably have to change it.
If you've already got this set up, then I'd probably have to test with a local share on my system to see what happens.
AMD FM1 x4 A8-3870 Llano, Gigabyte GA-A75-D3H, 4 Gb DDR3 Ram, Seagate 500 Gb, Seagate 1500 Gb, HVR3000 x 2 (DVB-S), Nova-T 500 (DVB-T), USB-Uirt, SPDIF -> Yamaha RX-V540, ATI HD6550 (OnBoard) > Samsung LA46A650 TV (HDMI), Harmony Remote 525
Windows 7 Ultimate x64 SP1, NPVR 2.4.3, AC3Filter, 1 x Popcorn Hour A-100, 1 x AppleTV with Plex