微信支付的时候报商户签名错误

Question

prepay_id已经获取成功，paySign签名的参数如下：appid="+appid+"&nonceStr="+noncestr+"&package=prepay_id=wx2015041419450958e073ca4a0071648005&signType=MD5&timeStamp="+timestamp+"&key="+keyhtml调用wx.chooseWXPay({appid:appid,nonceStr:nonceStr,package:'prepay_id=wx2015041419450958e073ca4a0071648005',signType:'MD5',//注意：新版支付接口使用MD5加密timeStamp:1429013035,paySign:'9522562E7050CA0104ECBF30ECEA33EB'});的时候就报错，商户签名错误，如何解决啊？