> the query that i am getting exception is
>
> Update IVITEMLOC
> set QTYONHAND=QTYONHAND+-23.0,
> averagecost = (((23.00000000) +(qtyonhand * averagecost)) / (23.0+
> qtyonhand))
> where ivitemid ='RBDPOLN' and ivlocid =1

Perhaps your QTYONHAND in the table is zero, which lead to dividing by zero:

> set QTYONHAND= 0 + -23.0,
> averagecost = (((23.00000000) +(qtyonhand * averagecost)) / (23.0 - 23.0))

Ivan
http://www.volny.cz/iprenosil/interbase