Disc Utility with no errors but file with input / output error

I have an external WD My Passport Studio hard drive of 500 GB with USB 2.0 and Firewire connections, and when I try to copy a .zip file from this external drive to the internal hard drive I can't do it. The Finder show a message like "can't read or write file".

I try to do the same using the cp command in the Terminal but it shows a message like this: "input / ouput error".

Obviously, the first thing I thought was "the file system has errors", and I tryed to check the external and internal hard drive with this Disc Utility, but there are no error.

Are there any other way to verify more deeply the file system? Or may be my drive is fisically damage? Why does the Disc Utility show me no errors?

Thank you.