The located assembly's manifest definition does not match the assembly

Im getting the error below when i try to build my web app. the same code work on my other machine, but not in the main dev. i have the dll in the bin folder, too. and the error discription is nothing more than the one given below? any ideas whats going on ?

Could not load file or assembly 'Microsoft.Office.Interop.PowerPoint12' or one of its dependencies. The l开发者_如何学Cocated assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040

Sounds like the Office (PowerPoint) COM components are not installed on that machine.