Problems with ADO .NET

Hi, I'm trying to pass a LongVarBinary data type parameter to a dynamic SQL,
but it gives me a Syntax error.
That is in order to insert a blob data type under Informix DataBase.

The code that I'm using is the following:

'*******************************

                 dim intValReturn as integer = 0
                 dim Table as string = "st_example"
               dim fieldblob as string = "fieldblob1"

                strQuery = "UPDATE " & Table & " SET " & FieldBlob & " = @parambyte"

                Dim spParamByte As OleDbParameter  'Crea parametro Byte

                Dim cmmUpdate As New OleDbCommand(strQuery, oCnx)
                cmmUpdate.CommandType = CommandType.Text

                spParamByte = cmmUpdate.Parameters.Add("@parambyte",  _
                      OleDb.OleDbType.LongVarBinary)
                spParamByte.Value = System.DBNull.Value 'buffer
                spParamByte.Direction = ParameterDirection.Input

                 intValReturn = cmmUpdate.ExecuteNonQuery() '<--In this line ocurrs 
                                                                                 '  the syntax error.
'*******************************

Is possible to do that in Informix DB

       Thanks.

         SugoiRam.
   (sugoiram@hotmail.com)