Thank you for coming back. I have version 6.07 running under both Windows 7 and XP, and, though I have found plenty of ways to break Eraser, this is one I have not seen.
This is guesswork. But I'd try the following things in order
If, by any chance, you installed Eraser 6 over Eraser 5, uninstall both completely, and delete any residual traces of Eraser you can find, including the Task List file and run a registry cleaner, such as the one in CCleaner, before reinstalling Version 6.
If your version 6 was a clean install, try just deleting the Task List files. Details of where to find it are in the FAQ; the index topic at the top of the FAQ list has a link.
At that point, I'm afraid you will need to try an uninstall, removal of traces (as described above) and reinstall of Eraser.
If that doesn't work, I hope that Joel can soon find time to come back on the forum, and advise.
David