[whpalmer4]

Only 18.9 MB? Do you have a lot of files embedded in there? That's about 6x the size of my database, and there are 4,884 actions at the moment. I've successfully synced via MobileMe with a database that the Finder reported as large as 75 MB, but it was very painful. Depending on what is making the database so large, you could be running out of RAM. It might be worth trying the operation again after powering down the iPhone (hold the top button until you get the red power off slider). Running the Archive Old Data command might also help (I had to do so when I first started using the iPhone app).

Probably the easiest solution is to summon the aid of the support ninjas as suggested in Brian's post and have them take a look with you. If the database isn't supposed to be so large, they can help you compact it, remove unwanted attachments, etc. Phone number is 1-800-315-OMNI if you prefer to talk.