WordPress MU

I have the MuWordpress running on the server now, but I still have problems with muplugins. Plugins uploaded in the plugins directory work fine, but if I try to use them as multi user plugins, I get errors or a blank admin page. I guess I should somehow enable the plugins in the site admin, but there is no option for this!

I also had some problems with user picture uploads, which I managed to fix with instructions from this forum (an htaccess issue). I wonder if this plugin issue could also be a htaccess issue?

mu-plugins is only for plugins that "must" be loaded for "every" user, on every page load.

The real need for putting a plugin in there is very, very small. 99.9999% of plugins should be in the normal plugins directory, where the user can access them and turn them on if they so choose.

If a plugin is in mu-plugins, it will not be shown on the plugins list for activation. They are automatically executed every page load, for every user, regardless if they want it or not.

Thanks for your answer, lunabite. It's hard to say if my need for muplugins is 99.9999%. Probably not, but still somewhere around 99.9% ;)
One of the plugins I've been trying to install in muplugins directory is Spam Karma 2. It is a multiuser plugin and according to the developers "just too complicated for most users". Besides, if there is a problem with one directory, there may be problems with the others too, so even if I wouldn't use muplugins, I'd appreciate some help with figuring out what the problem is.

Please search. Loads of us are using the SK2 plugin in the muplugins folder and there's even a modded version somewhere.

Spent a day searching, wrote cause I didn't find answers.

I'll keep on searching and if I find something I'll share it here. Thanks!

http://wpmudevorg.wordpress.com/project/Spam-Karma-2-for-WPMU

http://mu.wordpress.org/forums/search.php

I tried the upgrade script for SK2 from this thread: http://mu.wordpress.org/forums/topic.php?id=3563&replies=16#post-22504 . After I pushed the upgrade button I got this error: The requested URL /wp-admin/sk2_install.php was not found on this server. Which confirms my belief that my problem has nothing to do with SK2. htaccess perhaps? So now I'll start looking for an example htaccess-file for a subdomin installation. I'd appreciate if someone would care to share his/her htaccess-file.

The htaccess is created during the install process. unless you didn't install MU properly, or changed the htaccess in soem way, then yours would be pretty similar to mine.

"The requested URL /wp-admin/sk2_install.php was not found on this server. "

And you checked the files ot make absolutely sure it was there?

I can see the upgrade script the first time I go to the URL above. When I press the upgrade-button I get the message. I also tried with the mass mailer mu script (from http://wpmudevorg.wordpress.com/plugins.php ), uploaded it to mu-plugins, but nothing happened. Could not find it in the admin.

I don't believe Mass Mailer shows up in your Plugins list. You just go to WRITE --> WRITE EMAIL, and you will find it there.

the real question is why mails sent thru mass mailer appear to come from my domain host