Chuck I have tried it with IE, Opera, Chrome and Firefox and it does the same thing. It just does not make sense as it is member related.
Using any of the above browsers I can log in with one users profile and it will work with the flash. I then log in with another user and it will not work with flash but will work with the normal upload. I will make sure that that users profile is setup exactly the same as a user that it does work with as well.
I will setup an admin for you and PM you the details as well as the info for the one user that it does not work for