I installed Office 2007 Ultimate on my RDS (formerly TS) server, just as I've done with all the other apps I like to access remotely.  I installed the updates and service packs, but each time I tried launching any application (Word, Excel, Outlook) I encountered the following error:

 
This feature is not available.  For more information, contact your system administrator.

I finally realized this message was code for This product isn't supported in a Remote App environment!  I browsed around MSDN a bit and found that a different version of Office had a Volume Activation key.  Installing that version of Office, Office Professional 2007, with the available Office 2007 Suites VA1.0 key worked like a charm.

So remember to check for a Volume Activation license key, similar to the following screenshot, if installing an MSDN application as a RemoteApp.