DataDirect : Error " [DataDirect][SQLServer JDBC Driver]Invalid parameter binding(s)

[DumbCoder]

Hi,
Please help me out, I am trying to use DataDirect Driver and calling one stored procedure in SQL Server 2005. Constantly i am getting error on line "callableStatement.registerOutParameter(1, Types.INTEGER);"
Below is the code snnipette

Class.forName("com.ddtek.jdbc.sqlserver.SQLServerDriver");
String url = "jdbc:datadirect:sqlserver://141.128.92.68:3010";
Properties connInfo = new Properties();
connInfo.setProperty("user", "user");
connInfo.setProperty("password", "dev");
Connection conn = null;
conn = DriverManager.getConnection(url, connInfo);
CallableStatement callableStatement = null;
callableStatement = conn.prepareCall("{? = call pr_ReturnUserAccesssForAppln(@WinLoginID = ?, @AccessWrite = ?, @AccessRead = ?, @UserId = ?, @Name = ?, @FrostMil = ?)}");
callableStatement.setString("@WinLoginID", "devUser");
callableStatement.setString("@AccessRead", null);
callableStatement.setString("@AccessWrite", null);
callableStatement.registerOutParameter(1, Types.INTEGER); // Getting error at this line
callableStatement.registerOutParameter("@UserId", Types.INTEGER);
callableStatement.registerOutParameter("@Name", Types.VARCHAR);
callableStatement.setInt("@FrostMil", 1);
boolean results = callableStatement.execute();

Please let me know whats going wrong here?
Thanks