The "free" upgrade did the same to me. I remember seeing the link to "upgrade" DBC a while back. So, I did, and was able to enjoy experimenting with the new commands, gladly. Then one day, the programs I had written would not run anymore, due to the "trial" being over with. I was a bit flustered, seeing how I did not remember seeing a word about having to pay for the upgrade after a trial period ended. I do not usually complain. But, this did upset me at the time, and still does a bit now.
However, if I ever gain the funds, DBP will be my new partner.

+NanoBrain+