Ok, you got a cabinet file (.cab –> http://en.wikipedia.org/wiki/Cabinet_(file_format)) but you cannot extract it via (Extract.exe/Expand.exe).
Firstly, try 7-Zip –> http://7-zip.org/
Secondary, try Uniextract –> http://legroom.net/software/uniextract
Thirdly, try Unshield (*NIX) –> http://www.synce.org/oldwiki/index.php/Unshield
Finally, use Installshield resp. download the free trial and use the ‘InstallShield Cabinet and Log Viewer’ (IsCabView.exe) –> http://www.flexerasoftware.com/products/installshield.htm
Why all the fuzz? ‘Difficult’ CAB files are mostly newer Installshield CAB files (> approx. Version 9.0) which can only be easily opened via the IsCabView.exe.