Hi all.
Today I installed K2. It said "installation was successful" in blue. Below that it said "error building admin menus".
When I looked under components, there was no K2 link. There had clearly been an error building the admin menus :)
THE SOLUTION:
BEFORE YOU DO THIS PLEASE BACK UP YOUR DATABASE!
Log into phpMyAdmin (or try to find another way to edit your database)
Find your database (make sure it's the one for your Joomla! installation)
Within the database, look into the list of tables and find one called "menu"
(NOT the one called menu_type).
It's probably easiest to go to the last record (as it's likely the last thing you installed right?). Click on the [>>] button to do this.
Find anything with K2 in it, there was more than one for me, I assume the same for you too.
Delete these K2 entries.
Go back into Joomla and reinstall K2.
It should work fine this time. If it doesn't work, please ask again I don't mind
