Martin Stemplinger <mstemplinger@gmx.de> writes:

> today I upgraded to org-mode 7.4 (I'm using GNU Emacs 24.0.50.1
> (i386-mingw-nt6.1.7600) should that matter). Since then I receive the
> message "Unexpected Error" when I try to sync from Dropbox. 

I've been using 7.4 with my own webdav server (apache 2.2) with
MobileOrg and it's been fine.

I would suggest looking at the files in dropbox to see if they look ok.