It means the command can't find either the source file or the target directory.
This thread from AskUbuntu offers some hints for diagnosing the error:
Common possible errors:
File name is misspelled, including case (Linux is case sensitive).
Path statements are incorrect--try using full path statements.
Not in the desired working directory. Use pwd
("print working directory") to verify that you are in the desired directory.
For more assistance, provide some examples of what you've tried and what the output was.