Crystal Report Runtime Error

My colleagues are facing with the Crystal Report Runtime error whenever they try to save/print a pdf  file from the back end office. May I know how can I solve this error.

“An error has occurred while attempting to load the Crystal Reports runtime.

Either the Crystal Reports registry key permissions are insufficient or the Crystal Reports registry key permissions are insufficient or the Crystal Report

runtime is not installed correctly.

Please install the appropriate Crystal Reports redistributable (CRRedist*.msi) containing the correct version of the Crystal Reports

runtime (*86m, *64, or Itanium) required.”