I had a problem with my concrete5 site. Had an error on dephault.php line 68. Found that all dephault.php file were empty. I replaced them and it did not help. I looked in index.php files and found lines with internetcountercheck lines in code. I solved the problem by removing this line from code in all index.php files and replaced all dephault.php files. Be aware of these symptoms.. Is there any way to prevent this from happening again. Thanks.