ERROR 010240

Hi,

I am running a my own created model in arcGIS 9.3 version in Windows XP and it gave me an error.

"ERROR 999999: Error executing function.
The table already exists.
ERROR 010240: Could not save raster dataset to C:\Documents and Settings\Student\Desktop\Laptop Office backup Apr 09_2010\Lao_Data\NamNgumGeodatabaseDec14_2010\WEAP model.gdb\ExtractBanNalu_Nov_2085 with output format IMAGINE Image.
Failed to execute (Extract by Mask (35)).

All other models with same process run without any problem for all time periods but just one model stops giving me this error when it
runs the extract by mask process at one particular time step.

Can anyone help solving the problem. Help is highly appreciated.

Thanks,

Dumindu.