You cannot cd to a filename, or UNIX will give you an error message.
The system says "dirname not empty".
You are trying to remove a directory and there are files in it. Remove the files before deleting the directory. If you get the message, even though you think you've deleted all the files, use ls -a to check that there are no hidden files (names beginning with a period) other than . and .. (the current directory and its parent). To remove all hidden files, type rm .*.
The system says "cannot make directory ."
The directory that you specified to the mkdir* command already exists.