strange error with SVN LS command, when using another revision number

What does it mean:

$ svn ls -r 2195 ^/trunk
library/
$ svn ls -r 2195 ^开发者_开发问答/trunk/library
svn: File not found: revision 2263, path '/trunk/library'

What could be the reason of this strange behavior? Am I doing something wrong?

This is the solution:

$ svn ls -r 2195 ^/trunk
library/
$ svn ls ^/trunk/library@r2195
abc/

I don't know why, but now it works...