Make sure that some things can only be done in the wiki, forcing people to do it. Don't put people's e-mails in the wiki, force them to do so themself.
I second this point. Essentially, you don't want to be in the position of doing for your users what they "should" be doing themselves. While it sounds like you are there to support your users, you can support your users better with a bit of cooperation. From my experience with non-techies and wikis, I don't think it's a problem of not getting it so much as a problem of making it easier to learn how to use the wiki than continue not using it.
I second this point. Essentially, you don't want to be in the position of doing for your users what they "should" be doing themselves. While it sounds like you are there to support your users, you can support your users better with a bit of cooperation. From my experience with non-techies and wikis, I don't think it's a problem of not getting it so much as a problem of making it easier to learn how to use the wiki than continue not using it.