If Add2Exchange was working and now it's not, post here.
did you try this already from a previous post? http://support.diditbetter.com/kb/a2e_193.aspx
did you update to latest?
Also, extract and open the a2ediags.bat
and unregister cdo and reregister cdo
I've tried all of the above. Unfortunately, we have the same issue.
Sorry for the late response. I was out of the office yesterday.