I see no problem actually... I have all these 4 set up:

Code:
rene@thunder:~/.qmc2> grep ".dat" qmc2.ini | grep qmc2-sdlmame | grep FilesAndDirectories
qmc2-sdlmame\FilesAndDirectories\MameInfoDat=/home/rene/.qmc2/mameinfo.dat
qmc2-sdlmame\FilesAndDirectories\MameHistoryDat=/home/rene/.qmc2/history.dat
qmc2-sdlmame\FilesAndDirectories\MessSysinfoDat=/home/rene/.qmc2/sysinfo.dat
qmc2-sdlmame\FilesAndDirectories\MessInfoDat=/home/rene/.qmc2/messinfo.dat

When I "touch" the files and reload the game list my log will contain this (which looks good):

Code:
07:05:44.121: DAT-info database: importing system info-texts from '/home/rene/.qmc2/history.dat'
07:05:46.977: DAT-info database: done (importing system info-texts from '/home/rene/.qmc2/history.dat')
07:05:46.977: DAT-info database: importing system info-texts from '/home/rene/.qmc2/sysinfo.dat'
07:05:47.092: DAT-info database: done (importing system info-texts from '/home/rene/.qmc2/sysinfo.dat')
07:05:47.093: DAT-info database: 29393 game info records imported
07:05:47.932: DAT-info database: importing emulator info-texts from '/home/rene/.qmc2/mameinfo.dat'
07:05:49.276: DAT-info database: done (importing emulator info-texts from '/home/rene/.qmc2/mameinfo.dat')
07:05:49.277: DAT-info database: importing emulator info-texts from '/home/rene/.qmc2/messinfo.dat'
07:05:49.549: DAT-info database: done (importing emulator info-texts from '/home/rene/.qmc2/messinfo.dat')
07:05:49.550: DAT-info database: 11075 emulator info records imported


A mind is like a parachute. It doesn't work unless it's open. [Frank Zappa]