Although both .kcl and .szs files are related to Mario Kart video game for Ninento Wii consoles, a conversion between these two files seems unlikely. At best you can modify both of these files with tools, such as SZS Modifier or similar.
This conversion entry was verified by us and conversion was flagged as wrong or not possible.
Usually this happens when the conversion would try to convert different types of data between each other, such as audio to image, or it is not possible because incompatibility between programs, caused by closed file formats, very limited support etc.
If you find entry that you feel is flagged as bad wrongly, please tell us in the discussion below with as much as information as possible so we can fix it.