>I've done a few tests and I realized that the error I got since the beginning could be due to memory allocation.
>thst's what the help tells about the error 1152
>
>"You have attempted to select a table outside the 32K work area range or are attempting to reference a file variable in a table that is not open"
>
>If so... how can I manage the memory ?

Not sure that this has anything to do with memory.
Now that your new form has a private DS, nothing is open in that DS - or at least there's one table you forgot to open. Set a breakpoint in your error routine/method and in trace window go up to the line where it broke. See the alias in that line and you should find which table is it that you didn't open.