I have DP4 installed, never any issues. But since DP5 came out, I went into App Store and followed the prompt but it gives me a message saying that it can't be verified.. "tampered with or" etc.. it them restarts and goes through a install (i think it just undoes things it attempted to do). I've re-downloaded and retried to upgrade about 6 times now and not luck. In any case I still have DP4 and would like to get DP5. Any suggestions?