Maybe <Date 2008-09-11.14:02:59.998> was somehow rounded to :60?

I just got the same crash in roundup-admin and web interface.
In my case I got a journal entry with <Date 2010-10-28.14:34:60.000000>

My very ugly workaround was to change _utc_to_local() in roundup/date.py to:

    try:
        ...existing code...
    except ValueError:
        return (1970,1,1,12,0,0)