Thank you for your response! I tried DD 1.5.1 and it works, update to 1.6.3 and everything gone. No new missives, not even the esp is loaded. I think it's due to I still using Skyrim 1.597. But I have too many mods installed and I don't want to upgrade my game in fear of it may break these old mods. guess I will just have to skip Dirty Deeds.I have a working 1.6.3, on Skyrim version 1.6.640, if you are using any newer version, it could be the source of the problem.
I went from Dirty Deeds 1.4.2 to 1.5.1 (which introduces MCM but the functions did not work) to 1.6.3 and now everything works fine.
you can download 1.5.1 here and check if it brings up the MCM, then try to upgrade to 1.6.3 and finally get a working MCM:
You must be registered to see the links(source:You must be registered to see the links)
make sure to backup your save before any attempt at downgrading/upgrading.
And again, thx for your help.