SQL Exception on elements updates

2014-04-11 10:33:40 ***** ERROR ***** Exception-[HY000] SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction
2014-04-11 10:33:40 ***** ERROR *****    For query : update activity set idStatus='4' , done='1' , doneDate='2014-04-11' , result='Modif page + controller + requête prévisions'  where id=758
2014-04-11 10:33:40 ***** ERROR *****    Strack trace :
2014-04-11 10:33:40 ***** ERROR *****    #0 Sql->query called at [D:\xampp\htdocs\projectorria\model\persistence\SqlElement.php:666]
2014-04-11 10:33:40 ***** ERROR *****    #1 SqlElement->updateSqlElement called at [D:\xampp\htdocs\projectorria\model\persistence\SqlElement.php:399]
2014-04-11 10:33:40 ***** ERROR *****    #2 SqlElement->saveSqlElement called at [D:\xampp\htdocs\projectorria\model\persistence\SqlElement.php:308]
2014-04-11 10:33:40 ***** ERROR *****    #3 SqlElement->save called at [D:\xampp\htdocs\projectorria\model\Activity.php:233]
2014-04-11 10:33:40 ***** ERROR *****    #4 Activity->save called at [D:\xampp\htdocs\projectorria\tool\saveObject.php:56]

2014-04-11 10:20:36 ***** ERROR ***** Exception-[HY000] SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction
2014-04-11 10:20:36 ***** ERROR *****    For query : update planningelement set realEndDate='2014-04-11' , realDuration='2' , plannedWork='0.18' , leftWork='0' , realWork='0.18' , progress='100' , plannedCost='54' , leftCost='0' , realCost='54'  where id=1085
2014-04-11 10:20:36 ***** ERROR *****    Strack trace :
2014-04-11 10:20:36 ***** ERROR *****    #0 Sql->query called at [D:\xampp\htdocs\projectorria\model\persistence\SqlElement.php:666]
2014-04-11 10:20:36 ***** ERROR *****    #1 SqlElement->updateSqlElement called at [D:\xampp\htdocs\projectorria\model\persistence\SqlElement.php:399]
2014-04-11 10:20:36 ***** ERROR *****    #2 SqlElement->saveSqlElement called at [D:\xampp\htdocs\projectorria\model\persistence\SqlElement.php:308]
2014-04-11 10:20:36 ***** ERROR *****    #3 SqlElement->save called at [D:\xampp\htdocs\projectorria\model\PlanningElement.php:318]
2014-04-11 10:20:36 ***** ERROR *****    #4 PlanningElement->save called at [D:\xampp\htdocs\projectorria\model\PlanningElement.php:513]
2014-04-11 10:20:36 ***** ERROR *****    #5 PlanningElement->updateSynthesisObj called at [D:\xampp\htdocs\projectorria\model\PlanningElement.php:531]
2014-04-11 10:20:36 ***** ERROR *****    #6 PlanningElement->updateSynthesis called at [D:\xampp\htdocs\projectorria\model\Assignment.php:150]
2014-04-11 10:20:36 ***** ERROR *****    #7 Assignment->save called at [D:\xampp\htdocs\projectorria\model\Assignment.php:228]
2014-04-11 10:20:36 ***** ERROR *****    #8 Assignment->saveWithRefresh called at [D:\xampp\htdocs\projectorria\tool\saveImputation.php:100]