I setup a brand spankin' new confluence 3.5 wiki and tried doing an import of a 3.1 confluence wiki, but it wanted to take weeks for it to complete. I then tried it without attachments and the same thing occurred. Progress never passes 1%. I don't see anything helpful in the confluence logs.
My setup is using an external pgsql 9.0 database which connected fine in the initial setup.
My ultimate goal is to do a 3.1 -> 3.5 -> 4.3 upgrade.