Can't view configuration page in manager

I have just upgraded to 1.0.12 and all seems to be working as expected. But when I log in to the manager the configuration page is blank (the right frame). The rest of the manager console works just fine. Can anyone point me in the right direction to troubleshoot this?

Try clearing your browser cache and cookies for the domain. Sometimes the browser caches the old version of the .js files that were used, and they won't work in the updated Manager.

Good suggestion, thanks. But doesn't fix it. Looks like the page in the main frame is hanging but there is no error message. How can I reveal some sort of error to get a hint on where the problem lies?

If you have Firebug you might be able to find the error. Do you have access to the server's PHP error log? Sometimes, especially in the case of AJAX requests with don't impact MODx, errors won't show up in the MODx error log, but will show in the server logs.

In my apache logs I found:

PHP Fatal error: Call to undefined function mb_convert_encoding() in /var/www/***/manager/includes/lang/russian.inc.php on line 4, referer: http://***/manager/index.php?a=1&f=menu

I don't need Russian language support. This error seems to be because my system doesn't have dbstring installed. Is this required by Modx? Or is there a workaround? I don't really want to mess with the config of this server and this requirement wasn't flagged in the upgrade process. Any advice would be much appreciated.

Phew. Seems that you don't have 'php-mbstring' installed. Never had that package missing.

mb_convert_encoding is used at a few other lines in Evo (i.e. phpMailer) but it is not absolutely nessesary. But first you should look why russian language is selected as manager language - that should not be a default.

Hmm. Yes, thats odd and maybe I have been hacked. In the modx_system_settings table manager_language is set to 'english'. Is there a default somewhere else?

OK, I tried a completely fresh install of Evo 1.0.12 and had the same problem. Checking the logs I was getting similar errors due to missing php-mbstring functions. So I installed this module and all is well. I still can't explain the Russian default and just to be sure I think I will copy my content to a new install to make sure I haven't inherited any dodgy stuff.

Ok. Looked through the 1.0.12 and 1.0.13 code to catch a possible wrong $manager_language assignment. But I did not saw any problem with that. It is only set by config.inc.php + database and $_POST/$_GET during setup. So the only possibility is a wrong selection during installation or a faulty setting in an existing database.