Well, It seems that it was due to me running a Pro version prior to the upgrade. So, I reused the registration code, which worked and now I can record since it is a registered version.
Also, I do remember having asked this question directly to NCH about a year ago, to which they replied that they "had no clue" as to why this occurred, and what to do about it. That is when I upgraded my license for V6.
So, the question remains. How do I remove every trace of earlier Debut installations, so that when I install a new free version, it will start correctly asking me about using it non-commercially and letting me record, without having to buy a Pro license. the reason for asking is that this problem may occur in the future if the old license code would not be valid.