Upgrade to 5.1 Failed and resulted in a corrupted DB

Hi,

i tried to upgrade vCD 1.5 to 5.1, the VCD upgrade itself went ok but it failed on the DB upgrade:

Unable to upgrade the database: java.sql.SQLException: Violation of UNIQUE KEY constraint
'uq_os_name_version_update'. Cannot insert duplicate key in object 'dbo.os'. The duplicate key value is
(VMware ESXi, 5.1.0, 0).

when i tried to run the same DB command again, it came with an error that i need to restore my DB !!

any idea how to fix this??

thanks