> Just some shots in the dark:
>
> 1. Since exeption class is EIB... I supose you are using IBX.
> Is it "pure" IBX or there is some kind of "wraper" over it?

It is pure IBX. I am using InterBase components which come with Delphi
itself.

> 2. Which are the event handlers attached to that dataset?

There is really no event handler for this table.

> 3. Are you using any calculated fields?

No.

> 4. Are you aware a calculated field can only be assigned inside
> a OnCalcFields event handler?
> 5. What is the value for State property on that dataset when
> the error fires?

It is dsBrowse. When I click on another record in the grid. I also get
same error.

Thanks,
Can

> Ivan.