Data Report Aggregate problem..

hi guys,

i have created a datareport and it is working fine(picture enclosed of data-environment). but every time make any change in the report and run the report it is spitting an error. the error is "DataField 'Command3.Aggregate1' not found". The Command3.Aggregate1 is sum of "Command4.Aggregate1" ..

But when i remove the Command3.Aggregate and again create a new one., then the report works fine. this happens whenever i make any changes in the report(even if i draw a line). if i delete and add aggregate again, it works fine. I cannot figure why is this happening..

When i make an exe after deleting the aggregate and again adding it, the exe it works fine. no problem how many times i run the exe.

now i have to pass parameters and dynamically change the dataenvironement's connection etc .. so the command5(parent command) has to be refreshed. so it spits the same error dynamically.

now i thing i have two choices ., either i have to find why the error is happening and remove it, or how to dynamically manipulate the aggregate field and set it in runtime. so guys if anyone can help me then i'll be thankful..
if i am not clear in my question then do reply i'll try to explain it more detailed.