The permission problems you see are probably related to this bug: http://ez.no/bugs/view/6841 which was fixed in 3.6.2. You need to give your users read permissions to your pictures.
Don't know about the text problem. Where do you get that?
I get the text error in 50 % or more of my text in my mydesign. I have mainly had the same css code since 3.5.x, and in 3.6.1 there was no problem with my current stylesheets. But the "site design" that is in the same stylesheet is displayed correctly!