EAP 124.524 startup failure

When I start the newly-downloaded 124.524, I get the following:

"Plugin com.intellij failed to initialize and will be disabled:
Illegal constant pool index 46080 for method signature in class file com/intellij/util/xml/ui/DomCollectionControl
Please restart JetBrains RubyMine

The dialog does not actually allow me to click OK and I have to force-quit.

OS X Mountain Lion. This system was happily running the previous build of EAP, so this is a new issue.