When I load the plugin, the Options menu is not visible any more.
This the right frame after loading the plugin
I tried with unloaded compatibility but still don't work
This is how options it should look like
This tracker is not for third party plugins.
FYI, there is plenty of information about your issue available in the squirrelmail-plugins (and probably -users) mailing list archives. As a system administrator, you should also be capable of diagnosing blank pages, and if you are not, you should have read the SquirrelMail FAQ in the administrator guide or the mailing list posting guidelines before asking for help on the mailing list or simply doing an Internet search to learn how to do these things.
Your issue is also explained here: http://squirrelmail.org/wiki/CompatibilityDependencies