The Omni Group Forums - Unable to read document -- No root transactions found

In trying to use an OmniFocus database created during a trial period on my powermac onto my macbook, I'm constantly given this error. I have tried the FAQ procedure outlined at forums.omnigroup.com/showthread.php?t=5027 to no avail. OF works fine on the desktop with this db, and I never have both copies of OF open at the same time, and both are now licensed. I have tried mounting the db over the network, copying between the two, reverting to backup database, using either the working db on the desktop or a backup, but nothing works. I always get the same error message. Exporting to CSV, converting to tab-delim. in Excel and importing to OmniOutliner to export to OF import mangles the db too much to be useful. Any suggestions?