Can't remove public folder mailbox

I'm migrating from exchange 2007 to exchange 2010 and have a problem. Everything has migrated over ok but I cannot remove the public mailbox db from the 2007 server. I want to uninstall exchange before decomissioning this box but have hit a block wall.

This is a domain where we've has exchange for around 10 years, so there's likely some junk in there related to the old instalations.

This is a spanish language server, so some of the text is in spanish.

The source of the problem appears to be old offline address books which cannot be removed. The two appear below and refer to 'first administrative group' and 'Primer grupo administrativo' - which means the same in english and spanish... presumably created by different installers at one time or another... we've had lots of different exchange servers in this network.

When I try to remove the database it says that it contains replicas. There is nothing remaining on this box of any use:

get-publicfolder \ -recurse | select name, replicas

returns a list showing everything in the new public folder db except for IPM_SUBTREE

get-publicfolder \NON_IPM_SUBTREE -recurse | select name, replicas

returns a list showing everything in the new public folder db except for NON_IPM_SUBTREE and "EX:/o=IntegraXP/ou=first administrative group"

so I think I can safely say that the "EX:/o=IntegraXP/ou=first administrative group" public folder is the cause of my problems.

This what happens when I try to remove the public folder. It says to make sure I've correctly specified the identity of the folder.

    [PS] C:\>get-publicfolder \NON_IPM_SUBTREE -recurse | where {$_.name -eq "EX:/o=Integ
raXP/ou=first administrative group"}

Name                                                              Parent Path
----                                                              -----------
EX:/o=IntegraXP/ou=first administrative group                     \NON_IPM_SUBTREE\OFFLINE ADDRESS BOOK

    [PS] C:\>get-publicfolder \NON_IPM_SUBTREE -recurse | where {$_.name -eq "EX:/o=Integ
raXP/ou=first administrative group"} | remove-publicfolder

Confirmar
¿Está seguro de que desea realizar esta acción?
Quitando la carpeta pública "\NON_IPM_SUBTREE\OFFLINE ADDRESS BOOK\EX:/o=IntegraXP/ou=first administrative group".
[S] Sí  [O] Sí a todo  [N] No  [T] No a todo  [U] Suspender  [?] Ayuda (el valor predeterminado es "S"): s
Remove-PublicFolder : No se puede eliminar el objeto '\NON_IPM_SUBTREE\OFFLINE ADDRESS BOOK\EX:/o=IntegraXP/ou=first administrative
 group'. Asegúrese de que ha especificado la identidad correcta y de que cuenta con los permisos correctos para eliminarlo.
En línea: 1 Carácter: 135
+ get-publicfolder \NON_IPM_SUBTREE -recurse | where {$_.name -eq "EX:/o=IntegraXP/ou=first administrative group"} | remove-publicf
older <<<<
    + CategoryInfo          : NotSpecified: (0:Int32) [Remove-PublicFolder], MapiPartialCompletionException
    + FullyQualifiedErrorId : 3B3918E6,Microsoft.Exchange.Management.MapiTasks.RemovePublicFolder

Any suggestions. Everything is already on my new server, so I'm open to drastic solutions.

Thanks

Ian Murphy