xftp 链接 linux 上传失败

用 xftp 链接 虚拟机上边的 linux 中 的 tomcat  上传项目的时候，报错
错误信息如下：
STATUS:> Listing folder completed.
STATUS:> Listing folder '/j2ee/tomcat/webapps'...
STATUS:> Listing folder completed.
STATUS:> Listing folder '/j2ee/tomcat/webapps'...
STATUS:> Listing folder completed.


[#1 of '192.168.78.128'] Transfer failed: 'saa'.
[#1 of '192.168.78.128'] Starting transfer...
[#1 of '192.168.78.128'] Creating the folder 'saa'...
[#1 of '192.168.78.128'] Creating the folder failed.
[#1 of '192.168.78.128'] Changing to the folder 'saa'...
[#1 of '192.168.78.128'] Changing folder failed.
[#1 of '192.168.78.128'] Transfer failed: 'saa'.
[#1 of '192.168.78.128'] Starting transfer...
[#1 of '192.168.78.128'] Creating the folder 'saa'...
[#1 of '192.168.78.128'] Creating the folder failed.
[#1 of '192.168.78.128'] Changing to the folder 'saa'...
[#1 of '192.168.78.128'] Changing folder failed.
[#1 of '192.168.78.128'] Transfer failed: 'saa'.

这是怎么回事啊？ 
xftp 链接 以后，可以用命令启动和停止tomcat  啊，为什么不能上传项目啊？