Thanks for the quick reply, Scot...
Nope, no beta software... this is fairly standard production dev machine... VS.NET 2003 EA, VEA SP-2, Office 2k3 with all patches, SQL Server 2000, various dev utils, etc.
One more thing... it's working now. All I did was go eat my dinner. :-)
Honestly, I can't explain what happened. It didn't work... I closed Visio, ate my dinner, came back and opened up the same ORM source file that didn't work before, and bingo... OT works like a charm. One other difference I'm noticing between then and now is that I didn't see the toolbar icon before (when it wasn't functioning); I see it now. Odd.
I've done a little Office automation and integration work in my time, and it's definitely a strange beast... but I can't offhand explain this behavior. But if you're interested in reproducing the problem and want more details of my setup and configuration, let me know... I'll be happy to help.
Josh