Java Script Error when using live grid...

[broadsoft]

SmartGWT version 2.4.
Internet Explorer browser version 7.0.5730.13

Problem Description:
We have implemented live grid that shows over a thousand items. On scrolling the items we see a java script error as shown in the attached screen shot. Even after the error the live grid works, but we would like to get rid of the working.
The problem happens if the user quickly and continuously scrolls the contacts. If the scrolling is done slowly the issue is not replicated.
If we do a scrolling is done slowly so that all the items are fetched once, then the quick and continuous scrolling does not create any issues.

Thanks,
BroadSoft Team.

[Isomorphic]

Please provide minimally the JavaScript stack traces, any other errors or warnings in the Developer Console, and the code for the grid.