amoriset,
Sorry that you are seeing this issue. I could replicate it after installing SVN using update site.
Can you please remove / uninstall SVN and SVN connectors from MyEclipse (My Software section) and after restarting MyEclipse, please follow these steps to install SVN plugin :
a) Switch to MyEclipse Configuration Center > Software. Right click on Subversive plugin under Quick-Add Popular Plug-ins section and select ‘Add to Profile’.
b) When the dialog displays to ask about optional software, you can select the optional software from the related list presented or you can just skip.
c) Apply this change in the Pending changes section and follow the wizard to install the plugin.
d) On MyEclipse restart, you could see the SVN connectors are configured under Window > Preferences > Team > SVN > SVN connector (tab).
Our latest version is MyEclipse 2014, based on Eclipse Kepler (4.3). I recommend you download and install MyEclipse 2014 alongside your existing MyEclipse 8.5 to take advantage of the fixes and enhancements we made since the MyEclipse 8.x release. If you are currently holding a license for MyEclipse, then the same license can be used for MyEclipse 2014 too, as our license are time based not version based. Please take a look at this link for more information on MyEclipse 2014.
Let us know how it works for you.