Exchange 2007 Management shell issue: "There are multiple objects matching the identity "servername" Please specify a unique value"

Question

I thought this would be an easy answer to an issue I'm facing, but there's a problem executing the solution.
I'm running Exchange 2007 in a clustered SCC configuration.  The clustered resource is called "DENBURYMAIL."  I want to give my account full mailbox access rights to all the mailboxes in this resource/database.
I believe I found the solution to this at
http://technet.microsoft.com/en-us/library/bb310792%28EXCHG.80%29.aspx (about halfway down the page) the instructions read as follows: 
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 Q: I have a third-party messaging application that requires full access to each user's mailbox. With Exchange Server 5.5, we grant a special account the Service Account Admin permissions, and then tell the application to use this account. How
can I achieve similar functionality in Exchange 2007?
A: Exchange 2007 security works differently from that of Exchange Server 5.5. In fact, Exchange 2007 does not use a site service account. Instead, all services start as the local computer account.
If your logon account is the Administrator account, a member of the root Domain Administrators, a member of the Enterprise Administrators groups, or a member of the Exchange Organization Administrators role, you are explicitly denied access to all mailboxes
that are not your mailbox, even if you have full administrative rights over the Exchange system. All Exchange 2007 administrative tasks can be performed without having to grant an administrator sufficient rights to read other people's mail.
You can achieve the results that you want in the following ways, but do so only in accordance with your organization's security and privacy policies:
In the Exchange Management Shell, use the following command to allow access to all mailboxes on a given mailbox store:
Add-ADPermission -identity "mailbox database" -user "serviceaccount" -ExtendedRights Receive-As
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But when I run the command (Add-ADPermission -identity "denburymail" -user "matthew.fazio" -ExtendedRights Receive-As) I get an error telling me that "There are multiple objects matching the identity "DENBURYMAIL."  Please Specify a unique value."
I'm not sure what's causing this-- why are there "multiple objects?"  Is this a problem due to operating in a clustered environment?
Any assistance would be appreciated!

Answer 1

It may not be specific enough for the command to understand you.
Try this:
Get-MailboxDatabase -Server <servername> | Add-ADPermission -user "matthew.fazio" -ExtendedRights Receive-As