It happened to me too, in this link it says something about upgrading:
Windows users: Do not install Android Studio 0.2.x in the same
location as 0.1.x. Doing so may cause errors such as ClassCastException or
other unexpected behaviors. It's best if you remove your previous version
of Android Studio 0.1.x.
I fixed it uninstalling my currend Android Studio installation, removing
the folder where it was installed with the remaining files, and installing
it again. It works correctly now apparently.