Problem - copy backup file

Hi all , I’m trying to copy my backup file to my external HDD , but when I click copy button (I’m using winbox) the program stopped and says "winbox.exe stopped and i can click close or tell “Microsoft” about this problem , that is on Windows 2008 server, same situation work properly on “Windows Xp Professional , Windows 2003 Server” but on 2008 doesn’t work any suggestions ?

Try to copy backup file with some FTP client.