? Some questions...

Whu not Dolphin 7.1.5 or 7.2?
Why DU is better?

I try to install to test...
See attachment, what to do now? 

Who said DU was better?

Anyhow. The only issue in your screenshot is the disabled functions problem. Your host is restricting to many functions. Some of those functions are needed by dolphin. Even dolphin 7 requires them in some areas. You may be able to adjust that using a custom php.ini file. Ask your host how.

if someone can help me what to change? thank you.

Please also why i should change it.

Just another example of the confusion the naming of Dolphin U is causing. Utter stupidity.

You can't really blame the guy. It is a pre-release, get yer feet wet and get yer hopes up for a new project by Boonex to try and show they are actually doing something. The problem with that is there are no real setup instructions anywhere on the site. If you're not familiar with how they do things around here, you'll be totally lost trying to get a working copy up and running.

Maybe then make a club of people that can work on it.
Bacause i was thinking, i buy 7.1 and 1 year after the 8.0 is the... questions, questions.

Not everyone is a pro. 

I am thinking English is probably not your first language, but somehow you seemed to have summed up the issues nicely - almost like a haiku.