[SQLServer 2000 Driver for JDBC]Invalid parameter binding(s). 新手 求救。。

struct2  tomcat sql 2000 做的系统。在登录界面输入密码  用户 ，点了按钮后不能跳转 还是显示登录界面！ public String checkAccount(String account, String password) {
String sql = "SELECT ConNumber FROM Consumer WHERE ConNumber=? AND ConPass=?";
PreparedStatement pstat = null;
ResultSet rs = null;
Connection conn = new DBHelper().getConn();
String userid = null;
try {
pstat = conn.prepareStatement(sql);
pstat.setString(1, account);
pstat.setString(2, password);
rs = pstat.executeQuery();
while (rs.next()) {
userid = rs.getString(1);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
if (conn != null)
conn.close();
if (pstat != null)
pstat.close();
if (rs != null)
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return userid;然后出现下面的错误：信息: Server startup in 18368 msjava.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Invalid parameter binding(s). at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BasePreparedStatement.validateParameters(Unknown Source)
at com.microsoft.jdbc.base.BasePreparedStatement.validateParameters(Unknown Source)
at com.microsoft.jdbc.base.BasePreparedStatement.preImplExecute(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.commonExecute(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.executeQueryInternal(Unknown Source)
at com.microsoft.jdbc.base.BasePreparedStatement.executeQuery(Unknown Source)
at com.dao.UserDAO.checkAccount(UserDAO.java:107)
at action.Login.execute(Login.java:23)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:440)
at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:279)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242)
at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:163)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:249)
at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)是哪里错误了呢