Ok I think I fixed this myself.
If you have been searching high and low for an answer like I did then, you are probably pissed right now because you are thinking the following like I did.
"Hey WTF?!!! In addition to the $600 bucks I paid for this crap, I also bought the crappy book they recommended that only tells me how to build a quiz game!! Why did I have to search all over the internet then come here to read this guy's crap to get my answer?"
Well boys and girls, before you get your answer and if you are as mad as I was when I started looking for this then, I am asking you to do one thing before you use my answer. Send ADOBE a message or post a new message to this forum, asking ADOBE to improve their horribly horrible documentation. Its tragic how such a good suite of programs is hindered so much by very lousy upkeep of documentation.
This particular case is the worst example of many I have experienced. There are mislabeled subjects that have old and new versions mixed. There are outdated links to files that haven't been updated in years. There are third party references to developers who are nice enough to help ADOBE but if I am paying ADOBE $600/year for a product then, I shouldn't have to search forums, google and third parties for OUTDATED support to fix issues or just learn how to use the product. I should at least get the ******* worthless book that tells me the basic stuff on using the program along with the stupid quiz game with my $600/year purchase.
Anyway, off my soapbox and on to the help.
THE NEEDLE IN THE INTERNET HAYSTACK >>>>> I had to find an old apache forum: Re: mx.util Base64Encoder cannot be found Flash CS5
THE CLASS YOU NEED >>>>> That directed me to a Github site for Flex. flex-sdk/Base64Encoder.as at develop · apache/flex-sdk · GitHub
There you can download the right class file to get the compiler errors to stop. But your problems are not over if you used the typo filled and omissions in the crypto database guidance ADOBE gives us boys and girls. Noooope... More problems for you. LOL!! So If you are a newbie and still confused about what to do then I am sorry. Because now, I am purposefully not going to tell you how to get all of this running. I really want you to use your anger at me to direct it to ADOBE. I shouldn't be the one to tell you how to use a basic feature in their product. They should. They make billions of dollars on people just like you and me paying for a poorly documented product. Its time for this to stop and no one but us will make that happen.
If you are angry right now then I agree and feel for you but, let them have it, not me.