Plugin does not have valid header

Hi,

same problem on WP 3.3.1.

then I try to mv /wordpress/wp-content/plugins/all-in-one/all-in-one.php to plugins root (..nt/plugins/all-in-one.php) but after that, when try to active plugin, fatal error:

Warning: require_once(/usr/share/wordpress/wp-content/plugins/lib/iCalcreator-2.14/iCalcreator.class.php): failed to open stream: No such file or directory in /usr/share/wordpress/wp-content/plugins/all-in-one-event-calendar.php on line 249 Fatal error: require_once(): Failed opening required '/usr/share/wordpress/wp-content/plugins/lib/iCalcreator-2.14/iCalcreator.class.php' (include_path='.:/usr/share/php:/usr/share/pear') in /usr/share/wordpress/wp-content/plugins/all-in-one-event-calendar.php on line 249

Any help will be greatly appreciated ??

hey, i had the same problem, but after going to the full plugin list, I was able to activate it after all. This article was really helpfull for me:

https://webdesign.anmari.com/2312/activation-error-plugin-does-not-have-valid-header-still-activates/

good luck!

All I did was open the file all-in-one-event-calendar.php in the root of the plugin and on the first lines change the initial /** to /*

Then I went back and reactivated it. That got it working, and it took me to a splash page that said “All-in-One Event Calendar Notice: You are using the Lite Calendar. This edition of the plugin is no longer supported” And then a button to “Upgrade to the Standard Calendar for free”
I pressed that which installed an update, then automatically removed the old plugin. Now it works fine ??

I had the same issue and the solution above worked for me as well. Thanks Ian.