error in printing after purchasing an item

Can someone please help me with solutions on the printing issue with this item( Sales and inventory management system POS. error ……”unhanded exception has occurred in your application. Could not load file or Assemble. “CrystalDecision.CrystalReport.Engine.Version= Public key.Token.692feau5521e1304 or one of its dependences. The system cannot find the file specified.” Please i need help on this. Please. I have contact the author for this for over 10days now. no response.