DLL中调用Socket出现ASSERT有关问题

求助：DLL中调用Socket出现ASSERT问题！
在一个WEB应用服务器程序里，专门负责处理Browser客户端的请求，当接收到用户下载文件的请求后，调用一个DLL的函数去文件服务器获取所请求的文件。
文件传输的函数是用Socket实现的。在传第一个文件的时候没问题，当第二个下载请求到来后，WEB服务器调DLL里的函数出错了，

出错的地方在sockcore.cpp
的BOOL   CAsyncSocket::AsyncSelect(long   lEvent)方法：

ASSERT(pState-> m_hSocketWindow   !=   NULL);

查了网上一些帖子，说是多线程调用Socket出的问题，要使用Attach和Detach
来处理。我的Socket调用是封装在一个DLL里的，如下：

请问该如何修改？！！

int   getRemoteFile(CString   strIP,   CString   fName,int   port)
{

int   nRet   =   0;   //   return   value

AfxSocketInit(NULL);//should   comment   this   line?

CSocket   sockClient;
sockClient.Create();

sockClient.Connect(   strIP,   port);

int   dataLength,   cbBytesRet,   cbLeftToReceive;
//   pointer   to   buffer   for   receiving   data
//   (memory   is   allocated   after   obtaining   file   size)
BYTE*   recdData   =   NULL;
       
CFile   destFile;
CFileException   fe;
BOOL   bFileIsOpen   =   FALSE;
       
//   open/create   target   file   that   receives   the   transferred   data
       
if(   !(   bFileIsOpen   =   destFile.Open(   fName,   CFile::modeCreate   |  
CFile::modeWrite   |   CFile::typeBinary,   &fe   )   )   )
{
TCHAR   strCause[256];
fe.GetErrorMessage(   strCause,   255   );
TRACE(   "GetFileFromRemoteSender   encountered   an   error   ");
//AfxMessageBox(strCause);
/*   you   should   handle   the   error   here   */
               
nRet   =   -1;
goto   PreReturnCleanup;
}
       
//   get   the   file 's   size   first
cbLeftToReceive   =   sizeof(   dataLength   );
do
{
BYTE*   bp   =   (BYTE*)(&dataLength)   +   sizeof(dataLength)   -   cbLeftToReceive;
cbBytesRet   =   sockClient.Receive(   bp,   cbLeftToReceive   );
               
//   test   for   errors   and   get   out   if   they   occurred
if   (   cbBytesRet   ==   SOCKET_ERROR   ||   cbBytesRet   ==   0   )
{
int   iErr   =   ::GetLastError();
//TRACE(   "GetFileFromRemoteSite   returned   a   socket   error ");
/*   you   should   handle   the   error   here   */
                       
nRet   =   -2;
goto   PreReturnCleanup;
}
               
//   good   data   was   retrieved,   so   accumulate
//   it   with   already-received   data
cbLeftToReceive   -=   cbBytesRet;
}
while   (   cbLeftToReceive   >   0   );

dataLength   =   ntohl(   dataLength   );

//   now   get   the   file   in   RECV_BUFFER_SIZE   chunks   at   a   time

       
recdData   =   new   byte[RECV_BUFFER_SIZE];
cbLeftToReceive   =   dataLength;
       
do
{        
int   iiGet,   iiRecd;

iiGet   =   (cbLeftToReceive <RECV_BUFFER_SIZE)   ?  
                                            cbLeftToReceive   :   RECV_BUFFER_SIZE   ;
iiRecd   =   sockClient.Receive(   recdData,   iiGet   );

//   test   for   errors   and   get   out   if   they   occurred
if   (   iiRecd   ==   SOCKET_ERROR   ||   iiRecd   ==   0   )
{
        int   iErr   =   ::GetLastError();
        //TRACE(   "returned   a   socket   error ");
        CString   errMsg;
        errMsg.Format( "%d ",iErr);
        /*   you   should   handle   the   error   here   */
                       
        nRet   =   -3;
        goto   PreReturnCleanup;
}

destFile.Write(   recdData,   iiRecd);   //   Write   it
cbLeftToReceive   -=   iiRecd;

}  
while   (   cbLeftToReceive   >   0   );

PreReturnCleanup:   //   labelled   "goto "   destination

delete[]   recdData;                
       
if   (   bFileIsOpen   )
destFile.Close();
//   only   close   file   if   it 's   open   (open   might   have   failed   above)
sockClient.Detach();//detach   或许没用
sockClient.Close();

        return   nRet;
}




[解决办法]
创建一个不可见的窗口即可，因为只是用它做消息处理。
to ouyh12345() ：
CAsyncSocket和CSocket的线程安全是通过CWnd做消息处理实现的。
[解决办法]
我以前也遇到过类似问题,使用CAsyncSocket和CSocket类都会出异常,最后还是用winsock套接字的api解决的问题.