Hi Tommy,
Welcome to the forums!
I've moved this thread to the NEDweb sub-forum as I think you're having an issue playing videos from the NEDweb online player?
I'd recommend running Software Update form the Apple menu to make sure you have the latest version of Quicktime installed.
Also, does this issue happen with all videos or just certain videos from a particular tutorial?
Which browser are you using? If Chrome then try using Safari and log-out from macProvideo.com and go to Safari > Empty cache...
Then log-in to macProVideo and see if this helps.
I'd also recommend contacting our Support team
http://www.macprovideo.com/support/
They're better placed to help you out with technical issues.
Best
Rounik