Installation fails with an error:
0x80004005 dcom error
also, an error is logged similar to this in the Ex2007Config.log file:
ERR: System.Management.Automation.CmdletInvocationException: The term 'Get-PublicFolderDatabase' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
This issue is seen if you attempt to install PureMessage onto an Exchange 2010 SP1 server, in Hosting mode.
For more information refer to the Microsoft Knowledgebase article: http://technet.microsoft.com/en-us/library/ff923272.aspx
Known to apply to the following Sophos product(s) and version(s)
PureMessage for Microsoft Exchange 3.1.0
Exchange 2010, SP1, in Hosting mode
What To Do
PureMessage for Microsoft Exchange 3.1.0 did not provide support for Exchange 2010 SP1 in Hosting mode.
Customers should download and install any recent version of PureMessage (as of September 2012, 3.1.2) with their MySophos credentials.