I had a similar issue with my Windows7 PC to my 500X.
I hope that works for you!
If you have another PC or laptop make sure its not just your computer doing it.
My wife's Win7 box worked but mine had the same error as yours.
I ended up facing the fact that there are no more firmware updates coming out of Mede8er for the #00X line of players and reinstalled win7 to get it working for me.... A big PITA.