It looks like you have a template error in something that you use on many pages. I guess it's a header function. In CMS_FUNCTION is a context parameter that one can set - this could lead to the given error. I guess (for some reason), that SECTION isn't valid in the place where it's used. Could you please provide us more information about your used functions? Maybe we could take a look at your template code. It's hard to know without having the template code.
did Hannes' answer provide you with help? If so it would be great if you could mark the "correct answer". If you have already found a different solution, it would be nice if you could post it here so others can benefit from it.