Normally this error occurs when you upgrade the version of Cpanel.
To resolve this error follow the steps below:
1) Check the permissions for files.
2) Above files should have 755 permissions. If not then change the permission to 755.
3) Once the permissions are changed, execute the below command
Now error should be fixed.
If you are getting a blank page on phpMyAdmin,You may check this article to resolve the blank page error on phpMyAdmin.