PHP Warning: require_once(configuration_default.php) ...No such file or directory

[DrByte]

In a default original install of Zen Cart there is no file named configuration_default.php ... so this is not a bug in Zen Cart itself.
So, your configuration.php file must have been altered from the original if it's triggering that error message.

Therefore, I suspect it's a problem with one of the plugins you've added to your site. Since you didn't list any of that information, it's difficult to advise you further. Go back to all your plugins and determine which one expects a file named configuration_default.php and upload that file ... or remove the plugin that's expecting it by putting back the original version of the Zen Cart files.

[Awalji]

The last plugin I installed was css js loader. I have just uninstalled using uninstall.sql. It the configuration tab still doesnt seem to be working. I have also tried to find the files which were added to the server but there isnt any there. Is there any other of fixing this issue?

Thanks

[Design75]

You should check your FEC module. It is very likely you screwed that install up.