Stephanie,

We are still not ready for our digital release and we do not have a firm date yet. We were hoping for a late summer release, but have had some issues with the technological aspects. We will make a big anouncement once it is ready.

Sorry for the trouble. In our first printing, the unit 4 code was in the Pre-K book. The unit 5 code is RP05VIB. make sure you are using a zero between the P and V. Let me know if that still doesn't work.