文件下载时出现错误：
System.IO.FileNotFoundException: Could not find file 'E:\8zntx\temp\picture\45925.png'.
File name: 'E:\8zntx\temp\picture\45925.png'
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy)
at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
at KeLin.WebSite.PageWap.ResponseFile(String realPath, String fileExt)