>I belive that i understand the way,
>when the table is free table and not insert in database don't permit to select the fields
Vincenzo,
It permits for free tables too. You should select "other" to choose your free table. I'm becoming a pain in the neck but pls check your recordsource, columncount, column(ix).controlsources. Add a button to your form with this code in click event to check current status of grid :

*Button.click
*I assume your grid's name is grid1 if not change it
activate screen
? thisform.grid1.recordsource
for each oColumn in thisform.grid1
   ? oColumn.controlsource
endfor

Cetin