I'm getting the same results whether I install with a manual upload, or by using the web installer. When I go to activate the OIOpublisher plugin from the WP admin interface, all I get is the following error:

Error 500 - Internal server error

An internal server error has occured!
Please try again later.

I saw the earlier post about conflicts with the WP automatic upgrade plugin, but I don't see any such plugin listed on my plugins page.

Any idea where I should start looking?

indeed, the wp-content, plugins, and oiopub-direct directories all have 755 access.

I'll try out your suggestions

I'm using the official 2.8 release.

Update

• Upping the memory limit didn't affect behavior
• After disabling all othe plugins, I was able to load OIOpublisher. Haven't yet determined the conflicting plugin

Looks like it doesn't like Twitme either

No joy so far. I've installed the latest version of each plugin on a clean WP 2.8 install. I activated OIO first, then the other 2 plugins, but no internal server errors were produced. It may well not be a direct conflict.

It's a bit of a needle in a haystack situation, but it should be possible to track down. There are a couple of ways to proceed from this point:

1.) I give you some suggestions to try as / when I think of them.

2.) You send me Wordpress admin / FTP details via the contact form and I can track it down for you.

A couple of initial suggestions:

1.) I still think it might be something to do with the amount of allocated memory available (see this thread for some examples). It might be worth checking to make sure that your web host lets you change the memory level.

If you create a blank php file and put the code below in it:

<?php
ini_set('memory_limit', '70M');
phpinfo();
?>

Then search for 70M on the page when calling that file from your browser. If it's there (which means the change has worked), then can you try increasing the level to 128M in your wp-config.php file to rule out the issue completely:

define('WP_MEMORY_LIMIT', '128M');

2.) Did you add anything in your blog's .htaccess file (if you have one setup) besides the default Wordpress rewrite rules? If so, can you try commenting out the extra lines (by putting # before each line) to see if the 500 error continues.

Back to the drawing board then. I'll see if I can come up with anything else tomorrow.

I've sent you site/ftp access details -- please confirm that you've received them, either here or by email.

I believe I have resolved the issue by adding .htaccess rules to use PHP5 instead of PHP. I added the following to my .htaccess file:


AddType x-mapp-php5 .php
AddHandler x-mapp-php5 .php


I undid your changes and now it seems to be loading fine.

Also, I notice that OIO is loading wp-config.php directly. I have wp-config located outside of the web root, which has caused problems with some other plugins, though I see that OIO has some config option for this. If you were to load wp-load.php instead, it knows how to find wp-config for you. (I've had to hack other plugins to do this)