My b2evolution Version: Not Entered

I installed it and I got this error

Fatal error: Class 'BlogCache' not found in /www/hostrator.com/o/l/a/olabaz/htdocs/blog/inc/_core/_class4.funcs.php on line 74

when I tried to login. It doesn't even load.

http://olabaz.hostrator.com/blog

What do I do?