Can't copy files from my Passport Essential 320 GB

Hi,

recently I bought my Passport Essential 320 GB but I have problems with it. Using WD SmartWare  I can only backup my documents, pictures etc. So I simply copied my file (for example movie) to Passport Essential. And now it’s my big problem because when I’m trying to paste them on my computer Windows give me message “Cannot read from source file or disc”. What’s the problem and how to solve it?

P.S

I use Windows Vista Business

Service Pack 2

First thing is you have to log in to your computer as Administrator or have some Administrator right to do file copy or back up.

After you have all the rights needed for back up.

Start up the WD Smartware program.

Click on the Backup.

Click on the arrow next to Detailed View, to show all the categories.

Select only the Movies, Deselect all of the others.

You are now ready to back up just the Movies.

Click on the Run Backup.