insert into access

[archer]

i have an app which maintains an access DB and i have a problem with inserting data into it
i am using oledb.command and executing it as a nonquery command
when i use the sql string which is built in the app directly in access the insert doesn't make any problems
but when i try to run it in VB it always returns this error (attachment)
can anyone help?
thanks

[Thelonius]

Can you post your code for the Insert? Make sure you have an open connection.

[weijian]

object reference not set to an instance of an object... an error which got my jaw dropped for a while. it's just hte keyword new -- make sure you have all objects declared as new, like Dim objCmd as New OleDbCommand(strSQL, objConn) etc. without new would give you an error.

[archer]

Private Sub BtnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
Dim conAdd As OleDbConnection = New OleDbConnection(conExp.ConnectionString)
Dim comAdd As OleDbCommand
Dim comStr As String, den As String
Dim comInt As Integer
den = CStr(calAdd.SelectionStart)
conAdd.Open()
comStr = "insert into exp values(" + intID() + "," + intKat() + "," + CStr(txtSum.Text) + ",'" + CStr(den) + "','" + CStr(txtMemo.Text) + "')"
comAdd.CommandText = comStr
comInt = comAdd.ExecuteNonQuery()
End Sub