You are correct that we're not supporting 2007. However, I did install CC v2.0.5 on Outlook 2007 yesterday successfully.
It could be the add-in became disabled during install. I'm not sure what the equivalent instructions are in 2007, but in previous versions, here's what you would do (from our FAQ):
http://www.clearcontext.com/faq.html#reenable
The ClearContext Add-in has become disabled (or is not loading), how do I re-enable?
If Outlook terminated during operation, the ClearContext add-in could be disabled. The first step is to restart Outlook and see if that fixes the problem. If this does not work, follow the instructions below to re-enable:
1. In Outlook 2003 and 2002 (XP), Select Help > About Microsoft Outlook > Disabled Items and select the checkbox next to add-in:clearmail.dll.
2. If this doesn't work, in all Outlook versions, Select Tools > Options > Other > Advanced Options... > COM Add-Ins... and ensure the box next to ClearContext is checked.
Please let me know if either of these help. Thanks.