SQL ERROR

I have this log:
2017-04-28 09:45:17.528 ***** ERROR ***** [V6.2.2] Exception-[22P02] SQLSTATE[22P02]: Invalid text representation: 7 ERROR: invalid input syntax for type numeric: "Activity"
LINE 1: ... assignment.idProject= '40' and assignment.refId= 'Activity'...
^
2017-04-28 09:45:17.528 ***** ERROR ***** [V6.2.2] For query : select sum(notPlannedWork) as sumnotplannedwork from assignment where assignment.idResource= '126' and assignment.idProject= '40' and assignment.refId= 'Activity' and assignment.refType= '1860'
2017-04-28 09:45:17.528 ***** ERROR ***** [V6.2.2] Strack trace :
2017-04-28 09:45:17.528 ***** ERROR ***** [V6.2.2] #0 Sql->query called at [/var/www/html/model/persistence/SqlElement.php:2063]
2017-04-28 09:45:17.528 ***** ERROR ***** [V6.2.2] #1 SqlElement->sumSqlElementsFromCriteria called at [/var/www/html/report/detailPlan.php:328]
2017-04-28 09:45:17.528 ***** ERROR ***** [V6.2.2] Exception-[22P02] SQLSTATE[22P02]: Invalid text representation: 7 ERROR: invalid input syntax for type numeric: "Activity"
LINE 1: ... assignment.idProject= '40' and assignment.refId= 'Activity'...
^
2017-04-28 09:45:17.528 ***** ERROR ***** [V6.2.2] For query : select sum(notPlannedWork) as sumnotplannedwork from assignment where assignment.idResource= '126' and assignment.idProject= '40' and assignment.refId= 'Activity' and assignment.refType= '1728'
2017-04-28 09:45:17.528 ***** ERROR ***** [V6.2.2] Strack trace :
2017-04-28 09:45:17.528 ***** ERROR ***** [V6.2.2] #0 Sql->query called at [/var/www/html/model/persistence/SqlElement.php:2063]
2017-04-28 09:45:17.528 ***** ERROR ***** [V6.2.2] #1 SqlElement->sumSqlElementsFromCriteria called at [/var/www/html/report/detailPlan.php:328]