I have been getting the frequently talked about Error 4000 drive error message and I thought that it was one of the NC drives but it looks like the cover on the x axis ballscrew (the one that looks like a spring) has been fouling.
Has anyone else had this similar problem? Anyone know where I can get a new cover?

A error 4000 is a axis drive fault. As you have found out, the causes can be more than one. Cable, motor, drive, and in this case excessive current which the drive noticed and shut down.
The part number is in your parts book. If it is available from Hardinge is not known, but I have heard of people finding similar replacements on the internet.

George