are you perhaps using NamelessHosting? I am quite confused by your post
Does this only occur on the profile page or on all pages?
if it occurs on all pages it means you set an invalid path to fix this open the “core” folder in there is a config.php file open it and remove whatever is inside “path”
if it occurs on only the profile page it means the header.tpl file is missing to add it back open custom/templates/(template)/ and replace the profile.tpl file with the default file
You might’ve enabled friendly-url’s during the installation, your web server does not meet the requirements to run friendly url's therefore you get an error
to disable friendly-url’s you must open the “core” folder and edit the “config.php” file and set “friendly” to “false”
If you have anyone question feel free to ask :)
V2 pre-19 is not yet released ;)
Please contact the author of the cesium template regarding your issue.
The problem is caused by friendly-urls
in order to disable friendly urls open the “core” folder -> this folder contains a file called “config.php”
Open the config file set “friendly” to false