Looks like CMPS is not correctly configured for the way you have installed it. Usually the cmps_index.php file is outside the /forums folder. Is that how you intend to run it? If so, you should look at the instructions for running the forum and cmps in the same folder and make sure your path in cmps_index.php to correctly point to your forum. I think its not and that is why it can not find that function.
