problem with parameters.Refresh

Delphi 6 /UP2
When using  TADOStoredProc the following code produce an "Connection
interrupted" error in an EOleException:

 with DataModule.spSetMode do begin
            Parameters.ParamByName('@intVersion').Value:= 10
            Prepared:= True;

The error only occurs when parameters.Refresh is established. If no Refresh
is included, then the parameters are not recognized by the TADOStoredProc
command (Then the error is "Parameter 'parameter name' not found" in an
EDatabaseError exception).
If I use Open rather than ExecProc there is no problem, but there is no rows
to return.
What I'm doing wrong? Thanks in advance.