Ever since I "upgraded" Dropbox refuses to accept the uploads. If I export to 09 everthing works fine. This happens both in Page and Keynote so there is something in the file format that is crashing the upload.
The new keynote file format is really an "archive folder" and dropbox has issues syncing... They are working on a solution, the current work-around is the revert to the previous iLife version of Keynote. Sorry, this ***** for everyone.