In order to correct the path to the communication DLL, you can manually edit the path by double clicking it and editing it.
Now the important part: you   MUST   then press    ENTER!!!    otherwise the change will not be set and the old path will remain!
Press OK and the new path is set.
Instructions:
- in Codesys select  "Online / Communication Parameter"
- click  "New"
- give the new connection a name
- select the type of connection (usually "STW_FF_CAN")
- click "OK"
- verify the path points to the correct file. If not, manually correct the path