[O] org-tempo missing (require 'org)
org-tempo only works with loaded org as stated short before the (provide ... in a comment in the org-tempo file. So IMHO the (require 'org) in the first lines is missing. In 99% of uses it may work without this clause because org is even loaded for other reasons.
[O] Typo org-switchb org-iswitchb
Newest ... The manual and the guide talk about "org-iswitchb", the code contains only "org-switchb". Thanks