Could you please check after clearing caches & cookies of the browser, close the browser & reopen it. . . .
Try to check with different browser like IE,chrome etc.
I tried doing what you said but I am not able to get that particular ADC Toolkit training other than that all the others I could able to.
Can you post the exact URL that is failing for you?
For more complete information about compiler optimizations, see our Optimization Notice.