Android invalid keystore format

I published a unity app to the android market around 3 months ago.
I came back, and would like to publish an update to it (obviously with the same keystore)
Did something change in the time I was gone?

jarsigner error: java.lang.RuntimeException: keystore load: Invalid keystore format

I had a similar problem; mine were solved when I uninstalled SDK 1.7, and re-installed SDK 1.6u14. I also had to install the 32 bit SDK, as my 64 bit wasn’t working either.
Hope this helps!