Comment 6 for bug 769466

Thanks for helping debug.

I think that the problem comes from the date translation getting confused by the 2-digit years. I have changed calibre in two ways:
1) Date strings that for some reason are not understood are set to a real date instead of being set to nothing.
2) The default template for last_modified is set to dd MM yyyy.

This is enough for now, because last_modified will soon become a 'real' column, eliminating the issues that arise by using the custom column.