Red exclamation mark in system tray



So I am running Eraser on the blank space of a 160GB WD harddrive. It has been at it for 5 hours now and the progress bar shows the same 1/3 that it did pretty much immediately after i started.

The Eraser icon in the system tray has a red exclamation mark on the left side of it. Does this mean it is not working right or that my disk is damaged?

5 hours! (7 pass DoD standard).
Can this be right?