I am using NI Bandstand for my wind sounds.  My audio interface (M-audio Fasttrack USB) doesn't support midi, so I had to go this route.  I set up Bandstand to receive input via Maple Midi port 2, and VDL 2.5 to receive input through port 1.  If I open VDL first, it loads and works just as it should.  However, nothing works with bandstand.  If I open bandstand first it works OK, but nothing works with VDL (In fact, Kontakt player gives me a message about locking memory not working correctly if I open the programs in that order.)  Anyone know if these programs can coexist?  I have tried asking at the NI forums, but no one seems to understand what I am doing.  Any help toward the righ direction is appreciated!

My system:
Lenovo ThinkPad
Dual Core 2.6 ghz
2 g ram
Sibelius 4
VDL 2.5
NI Bandstand

If you have two standalone players running simultaneously (in this case, KP2 for VDL and Bandstand), be sure to check that they're  both outputting to the same audio interface. You may need to check with M-Audio to see if it's capable of outputting simultaneous audio from two separate programs. Depending on the driver or how you have it configured in each program, this may be something to look into.

Other than that, it would seem that the first bit of troubleshooting would involve figuring out if you have a problem with your MIDI routing going to two separate programs (from Sibelius) or if this is an audio issue. Perhaps you should start by launching both KP2 (VDL) and Bandstand, double-checking their audio settings, load some instruments in both, and confirm if you're able to get audio output from both programs as expected. If that's working properly, the problem may just be how you're setting your outputs via the Sibelius mixer when working in that environment.