I've a tricky problem making me mad:

1. Same application: one on a Window Server 2003, another on my Windows
XP development machine.

2. It performs a SQLDA.update() of a Dataset containing rows with some
field set to dbnull.value.

3. Result on my machine (form the SQL Profiler):
exec sp_executesql N'IF EXISTS(SELECT * FROM Richieste WHERE GUID=
@key0)
    UPDATE Richieste SET
GUID=@0,DbGUID=@1,EvGUID=@2,IDIncidente=@3,PROAnno=@4,PRONumero=@5,DataIncidente=@6,Targa=@7,TargaAltroVeicolo=@8,CognomeCoinvolto=@9,NomeCoinvolto=@10,DescrizioneIncidente=@11,AllegatiRichiesti=@12,UserID=@13,Data=@14,IPProvenienza=@15,IDStato=@16,IDAderente=@17,DataUltimaModifica=@18,Costo=@19,Commissioni=@20,DataDownload=@21,UserIDDownload=@22,IPDownload=@23,InformazioniAggiuntive=@24,idAssicurazione=@25
WHERE GUID= @key0
ELSE INSERT INTO Richieste
(GUID,DbGUID,EvGUID,IDIncidente,PROAnno,PRONumero,DataIncidente,Targa,TargaAltroVeicolo,CognomeCoinvolto,NomeCoinvolto,DescrizioneIncidente,AllegatiRichiesti,UserID,Data,IPProvenienza,IDStato,IDAderente,DataUltimaModifica,Costo,Commissioni,DataDownload,UserIDDownload,IPDownload,InformazioniAggiuntive,idAssicurazione)
values
(@0,@1,@2,@3,@4,@5,@6,@7,@8,@9,@10,@11,@12,@13,@14,@15,@16,@17,@18,@19,@20,@21,@22,@23,@24,@25)',
N'@0 nvarchar(4000),@1 nvarchar(4000),@2 nvarchar(4000),@3
nvarchar(4000),@4 nvarchar(4000),@5 nvarchar(4000),@6 nvarchar(4000),@7
nvarchar(4000),@8 nvarchar(4000),@9 nvarchar(4000),@10
nvarchar(4000),@11 nvarchar(4000),@12 nvarchar(4000),@13
nvarchar(4000),@14 nvarchar(4000),@15 nvarchar(4000),@16
nvarchar(4000),@17 nvarchar(4000),@18 nvarchar(4000),@19
nvarchar(4000),@20 nvarchar(4000),@21 nvarchar(4000),@22
nvarchar(4000),@23 nvarchar(4000),@24 nvarchar(4000),@25
nvarchar(4000),@key0 nvarchar(4000)', @0 = N'1.1.97C8.670F57F6', @1 =
N'3', @2 = N'0', @3 = N'0', @4 = N'0', @5 = N'0', @6 =
N'2006-02-07T00:00:00.0000000+01:00', @7 = N'BM832SX', @8 = NULL, @9 =
N'', @10 = N'', @11 = N'', @12 = N'5', @13 = N'claudio', @14 =
N'2006-05-19T17:29:05.9030000+02:00', @15 = N'127.0.0.2', @16 = N'-1',
@17 = N'9', @18 = N'2006-05-19T17:29:06.0900000+02:00', @19 =
N'16.8000', @20 = N'3.0000', @21 = NULL, @22 = NULL, @23 = NULL, @24 =
NULL, @25 = N'0', @key0 = N'1.1.97C8.670F57F6'

4. Result on Window Server 2003:
exec sp_executesql N'IF EXISTS(SELECT * FROM Richieste WHERE GUID=
@key0)
    UPDATE Richieste SET
GUID=@0,DbGUID=@1,EvGUID=@2,IDIncidente=@3,PROAnno=@4,PRONumero=@5,DataIncidente=@6,Targa=@7,TargaAltroVeicolo=@8,CognomeCoinvolto=@9,NomeCoinvolto=@10,DescrizioneIncidente=@11,AllegatiRichiesti=@12,UserID=@13,Data=@14,IPProvenienza=@15,IDStato=@16,IDAderente=@17,DataUltimaModifica=@18,Costo=@19,Commissioni=@20,DataDownload=@21,UserIDDownload=@22,IPDownload=@23,InformazioniAggiuntive=@24,idAssicurazione=@25
WHERE GUID= @key0
ELSE INSERT INTO Richieste
(GUID,DbGUID,EvGUID,IDIncidente,PROAnno,PRONumero,DataIncidente,Targa,TargaAltroVeicolo,CognomeCoinvolto,NomeCoinvolto,DescrizioneIncidente,AllegatiRichiesti,UserID,Data,IPProvenienza,IDStato,IDAderente,DataUltimaModifica,Costo,Commissioni,DataDownload,UserIDDownload,IPDownload,InformazioniAggiuntive,idAssicurazione)
values
(@0,@1,@2,@3,@4,@5,@6,@7,@8,@9,@10,@11,@12,@13,@14,@15,@16,@17,@18,@19,@20,@21,@22,@23,@24,@25)',
N'@0 nvarchar(4000),@1 nvarchar(4000),@2 nvarchar(4000),@3
nvarchar(4000),@4 nvarchar(4000),@5 nvarchar(4000),@6 nvarchar(4000),@7
nvarchar(4000),@8 nvarchar(4000),@9 nvarchar(4000),@10
nvarchar(4000),@11 nvarchar(4000),@12 nvarchar(4000),@13
nvarchar(4000),@14 nvarchar(4000),@15 nvarchar(4000),@16
nvarchar(4000),@17 nvarchar(4000),@18 nvarchar(4000),@19
nvarchar(4000),@20 nvarchar(4000),@21 nvarchar(4000),@22
nvarchar(4000),@23 nvarchar(4000),@24 nvarchar(4000),@25
nvarchar(4000),@key0 nvarchar(4000)', @0 = N'1.1.97C8.670F57F6', @1 =
N'3', @2 = N'0', @3 = N'0', @4 = N'0', @5 = N'0', @6 =
N'2006-02-07T00:00:00.0000000+01:00', @7 = N'BM832SX', @8 = default, @9
= N'', @10 = N'', @11 = N'', @12 = N'5', @13 = N'claudio', @14 =
N'2006-05-19T17:29:05.9030000+02:00', @15 = N'127.0.0.2', @16 = N'-1',
@17 = N'9', @18 = N'2006-05-19T17:29:06.0900000+02:00', @19 =
N'16.8000', @20 = N'3.0000', @21 = default, @22 = default, @23 =
default, @24 = default, @25 = N'0', @key0 = N'1.1.97C8.670F57F6'

As you can see on Windows Server 2003 I have the null values translated
with the default keyword which doesn't work with sp_Executesql (I
receive an error about missing parameter)

The problem must be of the machine, since if I swap Tables/Databases
the problem continue to arise on the Window Server 2003.

The Server SHOULD be updated with the latest version.

Any clue???

Can't seem to speed up Rows.Add in DataTable
Your kidding me right?
Cannot connect to MSSQL2005 (Local) Server?
Parameterized Query
Transaction Promotion problem