latex - no beamer classes

[Heiko Becker <heikobecker92@xxxxxxxxx>]

Hello everyone,

I'm preparing a latex beamer presentation. Therefore I installed the 
latex-beamer package from the AUR.
But when I try to compile my presentation with \usetheme{CambridgeUs}, I 
get a message, that the theme cannot be found, although I have it in 
/usr/share/tex-mf/... and I also did texhash.

Can someone help me?

Best regards,

Heiko