I have been trying to install K2 2.6.0, first in an Joomla 1.7.3 environment and when it did not work in 2.5.7. For some strange reason the component does not get installed. The component is listed in extension manager, the database has received the additional tables, the K2 menu appears but when you click on an item, it indicates that the component is not found. The physical files do not seem to be there.
Uninstalling can only be done by removing the item from the extensions table in the database?
Any clues? Should I try to copy the component files?

I moved on and copied the files from the installer to my server. When I open the Joomla admin menu and hit on one of the K2 sub-menu items, I get a 500 server error. The error log tells me that the system cannot find 'class K2HelperHTML in 'administrator/components/com_k2/k2.php on line 77. This class is found in 'administrator/components/com_k2/helpers/html.php, which apparently it can't reference.
Does that give any other clues?

Can anyone help?