SVN - How to Export Just a Revision

I have SVN setup on my local computer (Ubuntu) which I use for development and an SVN client running on a shared host box which I use a staging server, also my production server has the same setup. When I do an export, the entire project is getting exported which is absurd for small version release. I use the following command:

svn export -r 31 http://localhost.com/proj/trunk . --force --username myusername

And the entire project is exported once again. So I try a different way:

svn export -r 'COMMITTED' http://localhost.com/proj/trunk . --force --username myusername

I then get this error:

svn: 'http://localhost.com/egr' is not a working copy
svn: Can't open file 'http://localhost.com/proj/.svn/entries': No such file or directory

I wonder if I am just not using the correct SVN export command or if there is something inherently wrong with my SVN setup (this is my first time configuring SVN).

dav_svn.conf:

  <Location /proj>
 DAV svn
 SVNPath /var/svn/proj/
 AuthType Basic
 AuthName "SVN Repo"
 AuthUserFile /etc/subversion/passwd
 <LimitExcept GET PROPFIND OPTIONS REPORT>
    Require valid-user
 </LimitExcept>

Ideas? Please advise.