How do I fix this coding error?

I have been doing the Unity roll a ball tutorial, and whenever I try to put the coding in for movement I get.

“The Associated script can not be loaded. Please fix any compile errors and assign a valid script.” Any help I can get on this would be appreciated.

What compiler errors do you have? take a look at the unity console

Probably you have renamed the script after its creation.
Please report the name of the script and the name of the class in the script itself