A simple select does not work correctly

I created an ADOQuery object with the following simple SQL statement:

select * from MyTable
order by MyField

I displayed it in a DBGrid object. But in runtime one of the columns
( an integer column ) shows bad values. If I use the refresh button
on the DBNavigator object, it works well. If I call the Edit and then
the Cancel method of the query it goes wrong again.
It is a point of interest that in this case only datas in fields below
current cursor position in the grid are wrong (!).

I have no ideas why just that column is wrong and why just below
the cursor? I think I checked all datatypes everywhere.

I use Delphi5 and MSAccess 2000.

I'd thank if somebody can help me.