ERROR [HY000] Or ERROR [23000] At Random Times When Using Sql Native Client Via ODBC

The following (VB.Net) code causes exceptions at seemingly random times.
Any suggestions?
Not sure if the problem is in .Net's ODBC support or in Sql Native Client.

If MARS is off, usually after less than 100 loops:



Code Snippet

System.Data.Odbc.OdbcException was unhandled
ErrorCode=-2146232009
Message="ERROR [HY000] [Microsoft][SQL Native Client]Connection is busy with results for another command"
Source="SQLNCLI.DLL"
Turning MARS is on bypasses that error, so it will sometimes survive a thousand or so runs before hitting:




Code Snippet

System.Data.Odbc.OdbcException was unhandled
ErrorCode=-2146232009
Message="ERROR [23000] [Microsoft][SQL Native Client][SQL Server]Cannot insert the value NULL into column 'Number', table 'tempdb.dbo.#TempTable___..(shortened to fit).. _________000000002F3F'; column does not allow nulls. INSERT fails.
Source="SQLNCLI.DLL"
Code here:
(Console Application, empty database,
Visual Studio 2005, .Net 2.0, Windows XP,SQL Server 2005 or SQL Express 2005, Local or Remote)





Code Snippet

Module Module1

Sub Main()

'Dim connection As New SqlClient.SqlConnection("database=TestDB;server=.sqlexpress;Integrated Security=SSPI;") 'Doesn't crash
'Dim connection As New OleDb.OleDbConnection("Provider=SQLNCLI;database=TestDB;Server=.sqlexpress;Trusted_Connection=yes;") 'Doesn't crash

'Dim connection As New Odbc.OdbcConnection("Driver={SQL Native Client};Database=TestDB;Server=.sqlexpress;Trusted_Connection=yes;") 'Crashes
Dim connection As New Odbc.OdbcConnection("Driver={SQL Native Client};Database=TestDB;Server=.sqlexpress;Trusted_Connection=yes;MARS_Connection=yes") 'Crashes

VBMath.Randomize()

Dim run_count As Integer = 1
connection.Open()
Console.WriteLine("Connected!!")

While True
'connection.Open()

Dim testcmd As New Odbc.OdbcCommand("CREATE TABLE [#TempTable] (Number int PRIMARY KEY)", connection)
testcmd.ExecuteNonQuery()
testcmd.Dispose()
testcmd = Nothing

Dim dtTemp As New DataTable
Dim daTemp As New Odbc.OdbcDataAdapter("SELECT * FROM [#TempTable]", connection)
daTemp.MissingSchemaAction = MissingSchemaAction.AddWithKey
daTemp.Fill(dtTemp)
Dim cbTemp As New Odbc.OdbcCommandBuilder(daTemp)
Dim viewTemp As New DataView(dtTemp, Nothing, "Number", DataViewRowState.CurrentRows)

Dim i As Integer
For i = 1 To 1000
Dim test_number As Integer = CInt(Rnd() * 2000)
If viewTemp.Find(test_number) = -1 Then 'Keep it unique
Dim new_temp_row As DataRowView = viewTemp.AddNew()
new_temp_row("Number") = test_number
new_temp_row.EndEdit()
End If
Next

daTemp.Update(dtTemp)

'daTemp.Dispose()
'daTemp = Nothing

'cbTemp.Dispose()
'cbTemp = Nothing

'dtTemp.Dispose()
'dtTemp = Nothing

'viewTemp.Dispose()
'viewTemp = Nothing


Dim testcmd2 As New Odbc.OdbcCommand("DROP TABLE [#TempTable]", connection)
testcmd2.ExecuteNonQuery()
testcmd2.Dispose()
testcmd2 = Nothing

'connection.Close()
'GC.Collect()

'Console.Write(".")
run_count += 1
End While

End Sub

End Module

Usually the ".Update" triggers the exception, but sometimes the other sql commands do it.
Have tried various experiments with disposing of objects immediately when finished, but no effect.
Opening and closing the connection each loop seems to delay the errors, but it still happens eventually.