Using Sp_columns Stored Procedure Trouble

Hello,

I'm trying to use the "sp_columns" stored procedure to pull in some
information about a table in my db, but I'm continuing to get the same
error:

ERROR [42000] [Microsoft][ODBC SQL Server Driver][SQL Server]Procedure
'sp_columns' expects parameter '@table_name', which was not supplied.

I'm not sure why, but I've re-written my code several times and can't
figure out just why this error is happening.  Here's a snippet of
the code:

Private Function GetDataType(ByVal columnName As String, ByVal table As String) As String
        Dim con As New
OdbcConnection(ConfigurationSettings.AppSettings.Get("LiquorLiabilityConnection"))
        Dim com As New OdbcCommand("sp_columns", con)
        com.CommandType = CommandType.StoredProcedure

        Dim param As New OdbcParameter("@table_name", table)
        param.OdbcType = OdbcType.VarChar
        com.Parameters.Add(param)

        param = New OdbcParameter("@column_name", columnName)
        param.OdbcType = OdbcType.VarChar
        com.Parameters.Add(param)

        Dim dr As OdbcDataReader
        Dim name As String

        con.Open()
        dr = com.ExecuteReader() 'THIS TRIGGERS THE ERROR
        While dr.Read
            name = dr("TYPE_NAME")
        End While
        dr.Close()
        con.Close()

        Return name
    End Function

Any suggestions would be appreciated.