Are you using any Theme plugin?

You have a javascript error on your page which is breaking jquery.  Or you're trying to launch the embed from a lightbox or other dynamically generated content where the elgg_load* functions don't get called and the js/css don't get loaded (a known problem).

@sharon

no, I´m using the core theme of elgg.

@Matt

How can I fix it? I´m not a programmer. When I hit the embed content button everything looks normal, only the upload tab is not working correct.

Thanks fo the fast reply!

I can't tell you how to fix it because it could be anything.  You'll have to find the source of the javascript error.  Is it on every page?  On specific pages?  Try systematically disabling plugins and you might find a culprit.

I just found 1 issue on the upload tab from embed. The rest of the site is running without any problems. I tried to disable a lot of plugins but not sure which inetract wtih the embed plugin.

Thanks

• First turn off all non core plugins and try again
• If you are on chrome/ff use the inspect element and then click on the console tab to see what javascript error is shown there.

I'll give it a try tomorrow. Thanks for all the help!