problems about update svn to 1.6.1

[loody]

Dear all:
I follow the steps in
http://blog.lv25.com/2009/04/build-subversion-16-on-ubuntu-810.html to
upgrade my svn from 1.5.1 to 1.6.1.
But I find a wired problem.
The system cannot find svn when I type svn.
Below are my output:
$ svn
bash: /usr/bin/svn: No such file or directory
$ whereis svn
svn: /usr/local/bin/svn
$ echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
$

as you can see the location of svn is in my PATH, /usr/local/bin
But why my system complain it cannot find it.
I use "apt-get remote subversion" before installing svn 1.6.1.
Does the problem come from not clean clearly?
appreciate your help,
miloody