主题：[求助]在线升级失败，怎么回事？【已解决】

设置了ftp在线升级，出现如下错误，是什么意思？

.NET Framework 版本：2.0.50727.3053
Foxtable 版本：2012.11.29.1
错误所在事件：在线升级失败！
详细错误信息：
System.Net.WebException: The remote server returned an error: (550) File unavailable (e.g., file not found, no access).
   at Microsoft.VisualBasic.MyServices.Internal.WebClientCopy.DownloadFile(Uri address, String destinationFileName)
   at Microsoft.VisualBasic.Devices.Network.DownloadFile(Uri address, String destinationFileName, ICredentials networkCredentials, Boolean showUI, Int32 connectionTimeout, Boolean overwrite, UICancelOption onUserCancel)
   at Microsoft.VisualBasic.Devices.Network.DownloadFile(String address, String destinationFileName, String userName, String password, Boolean showUI, Int32 connectionTimeout, Boolean overwrite, UICancelOption onUserCancel)
   at Microsoft.VisualBasic.Devices.Network.DownloadFile(String address, String destinationFileName, String userName, String password, Boolean showUI, Int32 connectionTimeout, Boolean overwrite)
   at Foxtable.Syscmd.Project.Update(Boolean OlO1O, Boolean O011O)