Error in checkbox

Hi
I have the following error when I deselect a checkbox:
ResultSet:isc_ResultSet_13 (created by: isc_ListGrid_15):get: invalid index -339
It isn't a blocking error but I want to solve it if it is possible
can anyone have an idea about the origin of this error

I use
gwt sqk 2.3.0
smartgwt3.1 pro and LGPL
the browser: internet explorer8
Eclipse indigo 3.7, jdk 6u22