Well first kudos to all of you guys. I am using installer 002 for Outlook XP and it works great. I would like to install SpamBayes Outlook add-in on Outlook 98 on NT4 SP6 but I get: spambayes_addin.dll Unable to register the DLL/OCX: DllRegisterServer failed; code 0x00000000 Looks like that "good" ol' Outlook 98 does not support plugins in this way? Is there a workaround? Regards, Jocelyn