Connect to sql server using ole db provider

Using a javascript program i try to maintain a table defined in Sql server . Unfortunatelly the program can't update the table because the OLE DE PROVIDER cannot determine if you can write to each field . It returns for each field of the table , the field property adFldUnknownUpdatable .This value indicates that the provider cannot determine if you can write to the field. iT IS STRANGE TO ME BECAUSE I HAVE INSTALL MDAC 8 IN MY COMPUTER AND I USE THE MICROSOFT OLD DB PROVIDER FOR SQL SERVER .