It might be the servers are just overloaded with requests still.
My order just went through with no problems using the same card I did for the original purchase.
Now, i am certain that is it not a server overload, rather an error in the request form that seems to be inconsistant. Sure, a few lucky one get the right frame and they get there code but otherwise, if we consider only 1 server, at ~100request/minutes times 3 days....
I get 432 000 computer from June 6 through yesterday... That could be formulated in that timeframe... Lets divide that by 200, it makes 2160 persons that wants ther OS X lion... Even my old HP Pavillon can handle those request...
Conclusion=sever error or misconfiguration