I believe you just have to get the updated code the the in-app billing classes and you shouldn’t run into the same problem again.
Google hasn’t pushed out the changes to the SDK Manager yet as far as I know. Just copy/paste the new classes into yours and you shouldn’t run into the problem any longer.
Have a look at the new code changes here:
https://code.google.com/p/marketbilling/source/detail?r=7ec85a9b619fc5f85023bc8125e7e6b1ab4dd69f&path=/v3/src/com/example/android/trivialdrivesample/MainActivity.java
The classes that were changed as of March 15th are: IABHelper.java, Inventory.java, SkuDetails.java and some of the MainActivity.java file