Subclipse is not well supported in Eclipse Ganymede… I had a lot of issue, for installing and for using it, like Subclipse asking me for my ssh password all the time.
Now, SVN is directly supported in Eclipse, just follow these instructions (found here) :

Anyway, here are a set of steps which should result in a working Eclipse Ganymede with the new subversion:

Get the basic subversion integration plugin from the eclipse download site

1. Select Help::Software Updates from the menu bar
2. Unfold Ganymede::Collaboration Tools
3. Select SVN Team Provider (Incubation)
4. Click install… and follow the instructions, including a restart of Eclipse

Resist the temptation to try and use the plugin at this point. It won’t work and you will get the above confusing message about connectors.

Get the third party SVN connectors from a different update site

1. Select Help::Software Updates from the menu bar
2. Click Add Site…
3. Enter http://www.polarion.org/projects/subversive/download/eclipse/2.0/update-site/ and Click OK
4. Unfold the new site :: Subversive SVN Connectors
5. Select appropriate connectors. In my case I selected Subversive SVN Connectors, SVNKit 1.1.7, and SVNKit 1.2.0
6. Click install… and follow the instructions, including a restart of Eclipse

You should now be able to either Window::Show View::Other…::SVN Repositories or Window::Open Perspective::Other…::SVN Repository Exploring and add repositories to your hearts’s content.