Help with manual Install - 500 error with /api/auth

Dear BillRun Team,
i have some problems with the website on a cloud vps. I cannot login with the credentials because an 500 internal error.

I tried using php5.6, php7.1 and php 7.2. (always clean install). When i use php7.X i cannot install yaf-2.3.5 (needs php5.X). DB credentials are in the prod.ini and prod is set as SetEnv.
No matter using httpd or nginx i got this:
`PHP Warning: Yaf_Loader::autoload(): Failed opening script /var/www/html/billrun/application/helpers/Billrun/Traits/Api/UserPermissions.php: No such file or directory in /var/www/html/billrun/application/controllers/Api.php on line 17

“POST /api/auth HTTP/1.1” 500 5 "

Has anyone an idea?

Thank you