RasSetEntryProperties返回87异常

RasSetEntryProperties返回87错误？ - C++ Builder / Windows SDK/API
想写个创建L2TP的代码，RasSetEntryProperties返回87错误，何故？在网上搜了半夜，无法解决。

------解决方案--------------------
给你个原来我写过的你参考一下,这个是实现自动拨号的，要是创建连接就用里面注释掉的代码创建
[code=C/C++] //m_bConnected = !m_bConnected;
//GetStatus();
HRASCONN hRasConn;
RASDIALPARAMS rdParams;
DWORD dwRet;
char szBuf[512];
rdParams.dwSize=sizeof(RASDIALPARAMS);
strcpy(rdParams.szEntryName,"宽带连接");
//rdParams.szEntryName[0] = '\0';
rdParams.szPhoneNumber[0] = '\0';
//strcpy(rdParams.szPhoneNumber,"663");
//strcpy(rdParams.szCallbackNumber,"*");
rdParams.szCallbackNumber[0] = '\0';
//strcpy(rdParams.szUserName,"123456");
//strcpy(rdParams.szPassword, "123456");
//rdParams.szPassword[0]='\0';
//strcpy(rdParams.szDomain,"*");
rdParams.szDomain[0] = '\0';
hRasConn=NULL;
//LPTSTR lpszPhonebook;
//RasCreatePhonebookEntry(NULL, lpszPhonebook);
//RasValidateEntryName(lpszPhonebook,rdParams.szEntryName);
//RasSetEntryDialParams( lpszPhonebook,&rdParams,false);
// LPBYTE lpbDeviceInfo; // buffer that contains device-specific configuration information
// DWORD dwDeviceInfoSize ;
 // LPRASENTRY lpRasEntry;
  
//RasSetEntryProperties(NULL,rdParams.szEntryName,lpRasEntry,sizeof(LPRASENTRY),lpbDeviceInfo,dwDeviceInfoSize);
dwRet=RasDial(NULL,NULL,&rdParams,0L,(RASDIALFUNC)RasDialFunc,&hRasConn);
if(dwRet!=0)
{
 if(RasGetErrorString(dwRet,&szBuf[0],sizeof(szBuf))!=0)
wsprintf((LPSTR)szBuf,"Undefined RAS Dial Error (%ld).", dwRet);
ShowMessage(szBuf);
//ShowMessage("拨号失败，请检查配置！");
} else ShowMessage("拨号成功");
[code]