checkout ends with error

[Chris Carman]

I've searched for other occurrences/descriptions of this problem, but
haven't found any so far…

When I run the following checkout command, the directories are created as
expected, but the checkout ends with an error:

     svn co https://github.com/NUKnightLab/TimelineJS --depth immediates
     A    TimelineJS/branches
     A    TimelineJS/tags
     A    TimelineJS/trunk
     svn: E200004: Could not convert '' into a number

Further, when I then run status on the top level, it shows a modification:

     svn status TimelineJS/
     !       TimelineJS

But if I attempt an update, the process fails and leaves everything locked:

     svn up TimelineJS/
     Updating 'TimelineJS':
     svn: E235000: In file 'subversion/libsvn_wc/wc_db.c' line 1671:
assertion failed (SVN_IS_VALID_REVNUM(changed_rev))
     Abort trap: 6

     svn status TimelineJS/
     ! L     TimelineJS
       L     TimelineJS/branches
       L     TimelineJS/tags
       L     TimelineJS/trunk

I'm running on Mac OS 10.8.5:

     svn --version
     svn, version 1.8.8 (r1568071)
        compiled Feb 26 2014, 04:11:25 on x86_64-apple-darwin12.5.0

Thanks,

Chris