so the question is will it worke better with the real version...
What computer operating system is involved with your tryout Premiere Elements 14? Did you update 14 to 14.1 yet using an opened project's Help Menu/Updates. The details of the 14.1 Update can be found
The tryout is full featured. So, what you are experiencing should not be related to tryout versus purchased program.
My first impression from your description is that you should look to your computer resources.
When you say it cuts the audio, do you mean
a. there is no sound in the playback of the Timeline content after 30 minutes from the start of the Timeline content
b. audio and video goes out of sync
What is the total duration of the Timeline content when the audio problem exists at 30 minutes from the start of the Timeline content?
What are the properties of the Timeline content? Is the audio Stereo or 5.1 channel? What are your project settings? Please refer to Edit Menu/Project Settings/General.
Let us start here and then decide what next based on the details in your reply. Any questions, please do not hesitate to ask.