why do CollabNet Subversion Client and TortoiseSVN both update projects fine, but <svn> <update> within Ant fails

Question

I can manually update individual projects using CollabNet or Tortoise no problem.

But my ant script (executed from Hudson) containing

<svn javahl="false" svnkit="false" username="${svn.username}" password="${svn.password}">
    <update dir="${dest.path}/@{project}" />
</svn>

fails with

[svn] svn: 'C:\Hudson-slave\xxxxx\yyyyy' is not a working copy

[svn] svn: Cannot read from 'C:\Hudson-slave\xxxxx\yyyyy.svn\format': C:\Hudson-slave\xxxxx\yyyyy.svn\format (The system cannot find the file specified)

[svn] failed !

Could ant be using and older version of svn? How can I check which version it's using?

Answer 1

I'd use Process Explorer to look at the exact SVN command being run by ant. You should then be able to replicate the problem outside of ant.