Server Crash when running a query

[mmartinezpa]

I have been trying to run the following query using Mysql-nt 5.0.18:

SELECT FD_Time_Work_Of_Dt,
case fo_os_currency When 'MEXICAN PE' THEN 'MXP'
ELSE 'Otras'
end,

FO_OS_Risk_Category,
Seccion,
Seleccionada,
Sum(MontoFinal)
FROM reportes.quincenalTemporal
WHERE (Seleccionada>0)
GROUP BY FD_Time_Work_Of_Dt,
case fo_os_currency When 'MEXICAN PE' THEN 'MXP'
ELSE 'Otras'
end,
FO_OS_Risk_Category,
Seccion,
Seleccionada;

I can run it one time, using query browser. If I try to run it again, I get the following application error message:

The Instruction in "0x784ab333" refering to memory address "0x00000000". Memory cannot be written.

After clicking in the OK button the server stops.

I was running this query in version 4.0 with no problems at all.

Can anybody help me solving this?

Thanks in advance.
Mario