I think you also got errors when you try to click Edit button on Company Knowledge tab in SCOM 2007 as below
There is no more detailed information about how to setup VSTO in SCOM box. Here is a simple list for making sure you can edit company knowledge in SCOM.
1. Either SCOM installed on x86 or on x84, you just download VSTO SE x86 edition, and install it on SCOM server. Actually, I didn’t find VSTO x64 edition. Here is a link for download:http://www.microsoft.com/downloads/details.aspx?FamilyId=D8EB4921-891A-4B5E-973F-0B96E6CCF376&displaylang=en
2. Install Office 2007 on SCOM box, but you can just only install Word, no any other office application required
3. Recommend you install the latest office 2007 service pack
4. Now you can edit company knowledge, SCOM will launch winword and display a template for editing like below