The problem with the GCode you posted is there are no spaces delimiting the data. x4.55y6.78 should be x4.55 y6.78
1) The errors are caused by lack of space characters between data 2) Check the post processor settings for adding spaced between commands and data. 3) Incremental mode in KCam is only to be used when GC output was made unsing incremental mode in the generating program. I would avoid using it if given a choice. 4) Yes, KCam is saving a lot if parameters when the Option window is closed. That takes time.