Subversion Repositories WebE

Error running this command: svn --non-interactive --config-dir /tmp log --xml --verbose -r 20:1 'file:////home/mw3020/f001/svn/FFHS/WebE/trunk/src/ch/ffhs/webE/web/UserAction.java@20' --limit 2
svn: E160013: File not found: revision 20, path '/trunk/src/ch/ffhs/webE/web/UserAction.java'