I faced problem today while deploying my .net application on live server which uses crystal reports. I installed 64bit runtime of crystal report on server (ver 13.0.13). It was showing error for missing dll file "CrystalDecisions.ReportAppServer.CommLayer.dll". After so many tries I figured out that it was due to missing 32bit runtime, after installing 32bit runtime everything is working as it should be.
Hope it helps others using crystal reports and deploying application(s) on production server