ValueObject encloses an object's toString in quotes. A Boolean's toString outputs either 'true' or 'false', which are not accepted bit values for MySQL (and SQLServer if I remember correctly). I think most databases have true/false keywords for booleans and also properly convert '0' and '1'. My current work-around is to extend ValueObject to not quote-enclose Booleans.
Added a BooleanValueObject which outputs 1 and 0 for true and false (since sql92 doesn't have real booleans).
fixed in trunk, will be in the 2.0.4 release.