Dynamics GP - Product 309 does not support upgrading from version 9.0.300.

This is because a specific module has skipped an upgrade path.
The only solution is to either go back to the previous version and update it correctly, or delete the tables and reinstall the module for the current version. Of course you will lose all data that was in the module.

In this example, 309 is Fixed Assets

Solution from http://community.dynamics.com/gp/f/32/t/59532.aspx

1. UPDATE DYNAMICS..DB_Upgrade SET db_verOldMajor=0, db_verOldMinor=0, db_verOldBuild=0, db_status=0 WHERE PRODID=309 and db_name = 'xxx'

2. Delete DYNAMICS..DU000020 WHERE PRODID=309 and companyid = 'x'

3. Run the following scripts against the company database:

A. Drop table FA41000

B. Drop table FA00200

C. Drop table FAINST01

You can find the db_name and companyid in the SY01500 table.