http://bugs.winehq.org/show_bug.cgi?id=16592
--- Comment #11 from Paul Vriens Paul.Vriens.Wine@gmail.com 2009-01-15 08:23:25 --- GetVolumeInformationW is available on Win95/Win98 but calling it will set the last error to ERROR_CALL_NOT_IMPLEMENTED.
I ran your testcase on 95/98/NT4/W2K3 and in all cases it failed (tried both A and W-calls where possible).
Maybe it's better to attach some logging to the bug:
WINEDEBUG=+volume wine <your exe> > log 2>&1
(Remember to attach and not paste).