BuddyPress.org

Thx for help.
First its a single site. I already have permalinks set to day and name. Works fine.
If i deactivate BuddyPress, theme ist alright. (All themes that are not for buddypress, that i tested at least) I tried BuddyPress with qTranslate and qTranslate deactivated. Image uploaded to a post shows up without problems.

Do you have any other ideas what might be causing the issue? I am totally clueless right now.