I'm having difficulty running Exchange 2010 cmdlets through remote PowerShell sessions.

I start my local PowerShell session as Administrator and issue the following commands --

PS C:\Windows\system32> $mailcred = Get-Credential
PS C:\Windows\system32> $mailSession = New-PSSession -ComputerName MAILSRV -Credential $mailcred
PS C:\Windows\system32> Enter-PSSession $mailSession
[MAILSRV]: PS C:\Users\jdoe\Documents> Add-PSSnapin Microsoft.Exchange.Management.PowerShell.E2010
[MAILSRV]: PS C:\Users\jdoe\Documents> hostname
MAILSRV
[MAILSRV]: PS C:\Users\jdoe\Documents> Get-ExchangeServer
Value cannot be null.    
Parameter name: serverSettings
    + CategoryInfo          : 
    + FullyQualifiedErrorId : System.ArgumentNullException,Microsoft.Exchange.Management.SystemConfigurationTasks.GetExchangeServer

[MAILSRV]: PS C:\Users\jdoe\Documents> get-mailbox
Value cannot be null.    
Parameter name: serverSettings
    + CategoryInfo          : 
    + FullyQualifiedErrorId : System.ArgumentNullException,Microsoft.Exchange.Management.RecipientTasks.GetMailbox

As you can see, none of the Exchange cmdlets are working. What could be the issue?