Speculating now:
-- a bandwidth issue (although I'm sure you would have noticed a slowdown connecting to the other computers on the office network,)
-- problem with the AC client on the outside computer. (If it's a laptop that could be brought into the office, can you connect it as a client on the actual physical network in the office?)
-- AC Utilities has not correctly reset to the AC database through the Hamachi connection to the office server, and is still looking for AC on the physical network. (Need to get Hamachi connected first, then reset connection to the AC database in Amazing Utilities, then start AC on the client and redirect to the office database via Hamachi)
