Start at the top and work your way down. The errors given and the descriptions given should be enough.
If you are stuck on a particular error, post it here and we will sort it out.
Got some help at an Invision help forum and once the added styles had been broken out into a separate style sheet, everything worked.
Well, mostly. The +1 button displays correctly aligned in Firefox and Seamonkey, but all out of place on Chrome.