Version: 3.1.2+ (Build: 20160915)
I am trying to install a custom theme plugin, i come across
line 457 of /lib/upgradelib.php: plugin_defective_exception thrown
line 271 of /lib/upgradelib.php: call to upgrade_plugins_modules()
line 1449 of /lib/upgradelib.php: call to upgrade_plugins()
line 269 of /admin/index.php: call to upgrade_noncore()
as a result i am not able to install any plugin in moodle.
what is the issue and how can i fix it?