Please help me solve php error

Hello,
I am not very good technically, so please help me navigate this. I have installed OJS, everything worked for a while, and then the Installed Plugins Tab stopped showing the plugins. It is just stuck in loading mode. I have seen others with the same issue, and people asked for their php Error Logs, so here are mine

[Tue Sep 15 20:26:18.504688 2020] [php7:notice] [pid 13404:tid 1792] [client ::1:64400] PHP Notice:  Constant ORCID_IMAGE_URL already defined in C:\\xampp\\htdocs\\pmrp.online\\plugins\\generic\\classic\\ClassicThemePlugin.inc.php on line 18, referer: http://localhost/pmrp.online/index.php/pmrp/management/settings/website
[Tue Sep 15 20:26:18.505688 2020] [php7:error] [pid 13404:tid 1792] [client ::1:64400] PHP Fatal error:  Cannot declare class ClassicThemePlugin, because the name is already in use in C:\\xampp\\htdocs\\pmrp.online\\plugins\\generic\\classic\\ClassicThemePlugin.inc.php on line 20, referer: http://localhost/pmrp.online/index.php/pmrp/management/settings/website
[Tue Sep 15 20:26:18.779333 2020] [php7:notice] [pid 13404:tid 1788] [client ::1:64402] PHP Notice:  Constant ORCID_IMAGE_URL already defined in C:\\xampp\\htdocs\\pmrp.online\\plugins\\generic\\classic\\ClassicThemePlugin.inc.php on line 18, referer: http://localhost/pmrp.online/index.php/pmrp/management/settings/website
[Tue Sep 15 20:26:18.779333 2020] [php7:error] [pid 13404:tid 1788] [client ::1:64402] PHP Fatal error:  Cannot declare class ClassicThemePlugin, because the name is already in use in C:\\xampp\\htdocs\\pmrp.online\\plugins\\generic\\classic\\ClassicThemePlugin.inc.php on line 20, referer: http://localhost/pmrp.online/index.php/pmrp/management/settings/website

can you help me solve this?
please and thank you

Did you try do copy the classic theme file? It seems to me this file has been duplicated, therefore the declaration of the class in ClassicThemePlugin.inc.php is duplicate as well.

Kind regards
Daniela