>>>The same class with a table with 5 fields doesn't present the problem.....So the problem is in the number of fields ? What do you think ?
>>>
>>May be. Try adding fields back one by one until it breaks again. Then we'll determine the limit.
>The problem seems to be linked not to fields' number, but i have four fields that have problems.....three of them are Date fields and one of them is datetime.......but in the fields that don't create problems i have already date fields (2).....datetime no, but date yes.......
>Have you ideas ???

No, but I think Thomas also spotted a problem.