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.