I just came across this error in troubleshooting an MGADiag report to solve a non-genuine message on a Vista computer.
It took me a large amount of searching to find the right answer to it - so I thought I'd post my solution here in the hope that it gets a little easier to find for others in the same position CScript Error: Can't find script engine "VBScript" for script "C:\Windows\system32\slmgr.vbs".
This was preventing the Software Licensing Service in Vista doing what it needs to - and consequently giving rise to the non-genuine message, despite a perfectly genuine install.
The conventional response is to re-register the dll using regsvr32 vbscript.dll
This works fine in many instances - but in this case, although the registration gave rise to the 'succeeded' message, as it should (thereby showing that the dll was present), there was no change in the response from MGADiag.
The user had been using a registry cleaner - and this was in another forum, and she wasn't the world's most savvy user. All attempts to get her to properly follow reg query
Eventually, I got a clue to the problem from an obscure blog, which mentioned that some AV's blocked a particular registry entry, by substituting their own dll for the vbscript one.
The penny dropped at last - so I created a small reg file to put the default entry there instead.
Windows Registry Editor Version 5.00
with fingers and toes crossed, I sent her instructions to download and merge the file.
.....and it worked! The thread was by that time 45 long, with just the two of us in it.
Huge sighs of relief all round, and she's promised never to use a registry cleaner again.
So two victories for the price of one.
Not a bad result
 - and yes, it should also work in Windows 7 and XP [/edit] EDIT:
In a recent instance of this problem, Avast5 left behind incorrect values in the Classes\WOW64 area of the registry - these required more detailed hand-editing. Please post a NEW thread in the forum requesting assistance with as much detail as you can, and someone will assist.