I was getting this error on both Eclipse and Aptana when performing a checkout from an SVN repository:
Error validating location: “org.tigris.subversion.javahl.ClientException: Network connection closed unexpectedly”
svn: To better debug SSH connection problems, remove the -q option from ‘ssh’ in the [tunnels] section of your Subversion configuration file.
The weird thing was that I wasn’t getting the error when performing a checkout via the command line. Thanks to Google (again), I found the solution here: “Re: Problem Mac/Eclipse/Subclipse” after several combinations of search keywords.
The solution is simply to modify the SVN Interface from JavaHL (JNI) to SVNKit (Pure Java). You can do so under Window > Preferences > Team > SVN in Eclipse or Aptana.
Google-fu++!

Wish I would have found this a day ago! Exactly the fix I needed. Thanks!!!
Been googling for hours to make this work… Thanks very much
Thanks!! took me ages to find this!
Thanks for the tip. This worked for me great!
Awesome, thanks!
Thanks for your solution.