Success!
MAF tune flashed successfully and I just got back from a test drive. Niiiice!
While it's not a dramatic power increase, the whole driving experience is much much better. Somehow, the gear ratios got shorter.
Thanks to bimmerlabs, bimmergeeks and everyone who answers my dumb questions!
Some notes for those who have a working installation of Standard Tools and you are wondering how to get through all the steps.
I downloaded a copy of the latest E89 daten files and updated my installation with those (see youtube guides using BMW Coding Tool). Then in WinKFP step for importing .prg and .ipo files, I selected the folder with the downloaded and extracted the daten files (not my C:\EC-APPS.. locarion).
Since I already had all the files updated, WinKFP asks to ovewrite each one, which I did. I must've clicked 'Yes' well over 100 times.
Then when I proceeded to flash, I had the error in the screenshot above, so for both RSA delete and tune flash, I copied the .ctl and .0pa and .0da files to the directories indicated in the batch file. You can open the batch file in Notepad and see the path. RSAdelete took about 30 mins for me.
That's it. Thanks again!