By preventing the errors from WMIQuery(), I get the following results. Since I just prevented the errors by converting the array returned to a normal (non-array) variable, I can't guarantee the data is correct, but it no longer fails. You will still need to review the values returned from the WMIQuery calls.

I uncommented the message output of the product/CD Key processing to illustrate my earlier comment that only the last product is being logged.. You will need to create an array using something like this before the process loop:
 Code:
 Dim $aProducts  ; array of product data in prod,Key format
Dim $P   ; array pointer
$P = -1
Inside the current code, replace the "$CDKey = $Product + ': ' + $Key" line with the following:
 Code:
$P = $P + 1   ; increase array pointer
ReDim Preserve $aData[$P]    ; increase the array size, preserving prior data
$aData[$P] = $Product + ',' + $Key
You will now have an array of Product,Key pairs to work with. Note that the output below lists 4 products/keys found but only the last is in your report.

I also added code to show the processing time, after removing all of the Sleep commands and excluding the screen output to give you an idea of the WMIQuery performance.
 Code:
Asset Audit Script Processing...

  DBPath: \\server\...\IT-Inventar.mdb
CNstring: Driver={Microsoft Access Driver (*.mdb)}; DBQ=$DBpath
  CMDtxt: select * from COMPUTERS where computername = '@WKSTA'

Found Windows 8 Pro: PPC4M-WWWWW-XXXXX-YYYYY-ZZZZZ
Found Microsoft Office Professional Plus 2013: Q29K7-WWWWW-XXXXX-YYYYY-ZZZZZ
Found Microsoft Project Professional 2013: VB7FH-WWWWW-XXXXX-YYYYY-ZZZZZ
Found Microsoft Visio Professional 2013: M7FK3-WWWWW-XXXXX-YYYYY-ZZZZZ

Processing time: 15.325 seconds

MonHersteller: Samsung
MonitorDescription: SyncMaster 245T(Digital)
IP: 172. 16. 12. 16
Uhrzeit: 12:20:50
MAC:
PRIVILEGIEN: USER
COMPUTERNAME: ICWD011
OSNAME: Microsoft Windows 8 Pro
OSTYPE: Multiprocessor Free
SERVICEPACK:
INSTALLDATE: 20130105233330.000000-300
LASTBOOTTIME: 2013/12/10
OSSERIAL: 00178-10077-75869-AA763
SYSMANUFACTURER: Hewlett-Packard
SYSMODEL: HP Compaq 8100 Elite CMT PC
SYSSERIAL: 2UA04305JS
CPUDESCRIPTION: Intel(R) Core(TM) i7 CPU         860  @ 2.80GHz
CPUSPEED: 2933
VIDEOCARD: AMD RADEON HD 6450
VIDEORES: 1920 x 1200 x 4294967296 colors
MODIFYDATETIME: 2013/12/10 12:20:51
USERNAME: gbarnas
CDKey: Microsoft Visio Professional 2013: M7FK3-WWWWW-XXXXX-YYYYY-ZZZZZ

(ICWD011) - K:\ITCG\misc>

Edited by Glenn Barnas (2014-01-02 04:09 PM)
Edit Reason: fixed bad code tag
_________________________
Actually I am a Rocket Scientist! \:D