Header & Skin change

Help, we are trying to change the header and skin, we usually have no problem at all with this, however this time we have hit real problems and whatever we do it just doesn't work, we have tried sending it back to the old style and it won't go back properly, we have ended up sending it back to one we used in September and for the moment at least that one is working, has there been any changes to the set up that we don't know about?
Also would like to put some of the emoticons on here onto our forum, is there a way of doing this

for the forum restoring you have gone to...display // skins // themes management right?

for the smilies...display // avatars // smilies

Yes we have restored it but really would like to change the header and skin to a new one, but we can't do that without everything appearing jumbled up for some reason.
So we need to know what is going wrong and why and what to do about it
The smilies available on our forum are not the same as the ones on here and was wondering how we can import them onto our forum