I fixed it with removing the entry ("bib", "*.bib", "rekursiv", "schützen") under "Optionen" -> "Aufräumen" in TeXnicCenter. I'm using a german version so in english it should be something like: remove ("bib", "*.bib", "recursive", "protect") under "options" -> "clean up". Maybe you don't need to remove it but just change the action to do nothing.
Now I can use JabRef simultaneously.
All kinds of updating were useless before.
My versions are TC 1.0 RC 1 and JabRef 2.8.1.
hope this helps
