If im right 6 is the MMSYSERR_NODRIVER
Searching in the MMSystem Header of the WindowsSDK i get following results
Code:
MMSYSERR_NOERROR 0
JOYERR_NOERROR 0
MMSYSERR_NODRIVER 6
MMSYSERR_INVALID  11
JOYERR_PARAMS 165
JOYERR_NOCANDO 166
JOYERR_UNPLUGGED 167

so your programm doesnt find a driver for the last 6 joysticks

muffel