Disappearing buttons in dashboard

Hi all,

I encountered a problem I’ve never seen before: text are missing / buttons disappear from the dashboard and admin bar, but I don’t know why.
I made a dozen sites already, and I didn’t change a thing in the way I work with this project. (I develop WordPress websites locally, and when they’re done I move them to the domain name of the person I’m making the site for).

Locally everything works like a charm, but moved to the domain name I see the problems.

Perhaps the best example I can show you is the disappeared links on the admin bar. The top left WordPress button has some links, but these aren’t working: https://www.dropbox.com/sh/bcw4xxgbkuwsd99/VMF3kiAYHl/wp-missinglinks.jpg

The problem isn’t that the links aren’t there, but they haven’t got any text between the a-tags, so the link isn’t clickable.

Some other images of some of the problems I encounter:
– Missing buttons on plugins screen: https://www.dropbox.com/s/ovr766wbg53zj2q/wp-missing-plugin-buttons.png
– Alert popups without any text in them: https://www.dropbox.com/s/ukuxr0zezvbheia/wp-empty-alerts.png

I activated wordpress debug in wp-config, and got the following notice on the wordpress dashboard:
“Notice: in /home/<client folder>/public_html/wp-includes/functions.php on line 2998”
I don’t see any errors on the front of the site.

A notice without any descriptive text. Never seen that before either. I didn’t change anything to the WordPress core code, I only made a theme. The teme also doesn’t use a custom functions.php in which the error could be.

What I did to pinpoint the problem’s origin:
– Checked Firebug for Javascript errors or 404’s, didn’t find any.
– Verified PHP/MySQL version. It’s PHP 5.3.27 and MySQL: 5.5.32-cll.
– Disabled all the plugins. The problem is still there without any plugin active.
– Activated the debug function in wp-config, see above.
– Checked the file permissions on the ftp: files have 0644, folders have 0755.

Other problems I encounter:
– Redirects don’t seem to work: I’d like to have nice urls, not the ‘?page=8’ ones. But if I set wordpress permalinks to the right setting, the site still has the ‘?page=8’ links.

So, the problem in short: Link texts are (randomly?) disappearing from the wordpress admin area. Visitors don’t see any problem, it’s a admin area thing.

Hope to hear from you, because I haven’t got a clue where the problems are coming from!