Two days ago one of my clients had a similar problem in AR v9.2. They did a revaluation. The listing was perfect but when they posted the revaluation the revaluation rate was set to 0.00000 and the date to 12/31/1899, so the home currency was set to $0.00. Checking the database the last revaluation rate and date fields were blank. As they didn't have a recent backup I did a new revaluation to restore the Home amount and asked them to make sure they do a backup before the next revaluation and call us back if the problem reoccurs.