An alternative if you have Citrix WinFrame (wfapi.dll) is this small executable:
http://www.sgbit.demon.co.uk/files/ctxcinfo.exe

This will output the same sort of details in an INI format which can then be read with ReadProfileString(). I redirect this to a file in all my users home directories as they log on. It makes identifying the owner of a remote PC a doddle when the helpdesk records are incomplete or out of date.

Sample output:


[CTXCINFO]
WFVersion_MAJOR=2
WFVersion_MINOR=18
WFVersion_BUILD=663
WFVersion_CSD=Service Pack 3
WFClientBuildNumber=17534
WFClientName=SGB007968
WFClientDirectory=C:\PROGRA~1\Citrix\icaweb32\
WFClientProductId=0x1
WFClientAddress=10.9.2.139
WFClientDisplay_HRES=1247
WFClientDisplay_VRES=937
WFClientDisplay_DEPTH=2
WFClientCacheMem_TINY=32768
WFClientCacheMem_LOW=3145728
WFClientCacheMem_XMS=0
WFClientCacheMem_DISK=0
WFClientCacheDim_SIZE=0
WFClientCacheDim_MIN=0
WFClientCacheDim_LEVEL=0
WFClientCacheDim_OVERHEAD=0
WFICABufferLength=2048
WFInitialProgram=
WFApplicationName=#SGB Desktop
[WFClientDrives]
C=2
D=9
G=4
H=4
I=4
J=4
P=4
Q=4
X=4