Start a new project and open it. Close the project and Pr. Relaunch Pr, and you should be good to go. The presets that utilize licensed codecs typically need to be serialized to your install, which is done after an initial launch.
Should that not work, post back...
Thanks for your suggestion Colin but unfortunately, it didn't solve the problem.
I also tried starting Premiere with Alt + Shift key pressed to reset the preferences but with no luck.
Any other tips?
Download the trial again.
Are you connected to the internet when you installed / launched Premiere? The installer allows for an installation to complete on a system that does not have internet access but you will not get any 'protected content' files like the DLSR presets enabled until the system is connected to the internet (to execute in trial mode).