Hello
I have had the same identical problem told by this forum in first post two days ago like this
"Hallo,
I bought upgrade of RC8 for my RC7 and used it for over 1 year. Few times I had to re activate it during one year, but now I cannot reactivate it 
it shows 2005 error. Any thoughts how to fix this beast?
Thanks and Cheers, Pingu"
It happened after I changeìd BIOS in my computer, now my aerofly rc8 dosn't work, IT WANTSERIAL NUMBER BUT THEN IT SAYS error 2005, NUMBER already exists... but of course password exists: IT IS MY PASSWORD !!! I BOUGHT IT TO IKARUS, AS YOU CAN EASILY VERIFICATE
Now i canì't open my rc8, PLEASE can you tell me how to do it?