Get K2 in Joomla working fully

I have an install of a customised Joomla template which came with K2 installed in a quick start packj2.5. There are certain things not working properly, getting a php error on 3 of the top level backend tabs and the gallery upload is not working.

I'd like the whole thing to be fixed and in full working order along with a the gallery thumnails under the main image on an item on the front end template.