The Subversion plugin only works with RC2, sorry. This first version had a few shortcomings, which is why I completely abandoned it with plans to do a complete re-implementation.
Unluckily, time did not allow for that yet. As soon as the critical open issues for RC3 are fixed, I'll reimplement that plugin for RC3.
For the RC2 Subversion plugin to work, it has to be able to find the svn executable. It will query the Windows registry (there is a key for the installation path if you used the Subversion installer) and looks in a variety of places, including (if I remember correctly)
C:\subversion,
C:\tools\subversion and
%Programs%\subversion.
If it is still unable to find the executable after searching in a couple of places, it will assume that svn.exe is in
%PATH% and just call
svn.exe without an absolute path.
The path can always be changed in the preferences later, too (unluckily, you never get there if it crashes...).
There should actually be no harm if calling the executable fails alltogether, but unluckily the binary coming with RC2 was compiled from a version that has a stupid typo, so this actually crashes