I suppose, queryParams is some Collection of some type of DbParameter but not of type MySqlParameter. Thus you'll have to copy the names and values into new MySqlParameters like this:
MySqlParameter newParam;
foreach (DbParameter queryParam in queryParams) {
newParam = new MySqlParameter(queryParam.ParameterName, queryParam.Value);
cmd.Parameters.Add(newParam);
}
Otherwise I don't see what's going wrong there.