The following worked for me:
http://www.qliktips.com/2010_08_01_archive.html
The registration key of vbscript under ( 32bit and 64 bit versions)
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{B54F3741-5B07-11CF-A4B0-00AA004A55E8}
or
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{B54F3741-5B07-11cf-A4B0-00AA004A55E8}
is wrongly repeated under HKEY_CURRENT_USER. This would explain why sometimes running the installation as an administrator sometimes works.