Error Writing to the File

I get an error E000400003: Error Writing to the File whin I attempt a backup. I'm not the most diligent backer-up so it is some time since I have done one and many MS updates have been applied since! The last backup was dated Jan 2010 and this validates OK. The OS is XP SP3. The error occurs whether I use a network share (Linux - Samba) or the E: Drive. I have installed a new drive for E: and still get the same error (both Seagate ST3160215A ntfs format with Acronis install routine).