Group: current SVN version
Scons 0.98 was recently released and it is now, e.g., the version shipped to Fedora 8 systems (it updated a few days ago).
Due to some deprecations in scons, they have changed some of the *Option classes, such as SCons.Options.BoolOption. Previously, they were modules and Blender's build system is doing "import SCons.Options.BoolOption".
Now, however, BoolOption is a reference to SCons.Variables.BoolVariable, so you cannot import it the same way (it has to become something like "from SCons.Options import BoolOption").
Grepping the code, it looks like tools/btools.py is the only file that has a problem here and I suspect the above import change should make things work for 0.98 and older versions (but I don't have any older version around to test at the moment).