The database owner does not have necessary permission.  Set the DB Owner to an appropriate account, such as SA; and re-run Database Revisions

Please contact the appropriate software vendor or IT professional for assistance with this process or issue, which is beyond Blackbaud's scope of support.

Another solution that doesn't involve changing to the SA account is outlined in Microsoft's knowledgebase article:
http://support.microsoft.com/kb/913423

To work around this problem, change the database owner to a valid login or domain user. To do this, run the following statements:

USE <DatabaseName>
GO
sp_changedbowner '<NewLogin>'

Note <DatabaseName> represents the name of the database. <NewLogin> represents the name of the login that you want to set