I've been using this trick for years now, but everytime that I do a re-install of my workstation, or am at someone elses computer I end up relying on google to find out how to do it again. I don't need to do it often enough that I actually remember the details.
The problem is that Outlook 2002 blocks attachments with an extension that could execute. So, things like, *.exe, *.mdb, etc.. I don't get files like this very often, but when I do I tend to need them in a hurry. To cut a long story short, if you need to get access to a blocked attachment then:
The 'Level1Remove' string should include a semi-colon delimited list of file extensions that you want Outlook to stop blocking. For example, right at the moment mine contains 'vb;mdb;'.