Can't get CodeIgniter working under Linux *SOLVED

[eluser]Frychiko[/eluser]
Having trouble trying to get CodeIgniter working under Linux (Ubuntu 11.04) working with a local LAMP setup. I've set up some files the same as in the video tutorial with the blog controller as a test.

Code:

localhost/ OK
localhost/ - "Index of /" - OK - file listing
localhost/mysite/index.php - "Welcome to CodeIgniter!" etc.. OK
localhost/mysite/index.php/blog/ - "Server error." FAIL, it's HTTP error 500.

I can't access anything past index.php. I haven't created any .htaccess file yet.
Controller name capitalized. Index function check.

[eluser]Frychiko[/eluser]
Turns out there was a typo causing the 500 error. Solved. This can be deleted, if that's possible.

[eluser]Vlad11132[/eluser]
Excuse me for my not very well English. I don't know to install codeigniter on linux? help me to install codeigniter on linux, please.
Vlad