photoloss the dev.exe came with 1.16 & later, also you are correct with the pre-entrenchment path to the mods folder.
the mods folder changed when entrenchment was released to two/later 3 trees the mods-v1.###(original sins), mods-entrenchment v1.###(entrenchment) and since diplomacy mods-diplomacy v1.###.
and for the public released 7 deadly sins it is for sins 1.05 ONLY and did not even work with the later patches to vanilla sins before entrenchment, so to get it to work you NEED to install the sins from dvd for version 1.00, then download & execute the bonuspack to 1.05( the patch) , put the extracted 7deadly sins into your mods folder, start sins & go to options/mods and activate the 7deadly sins, then drop the detail settings to medium and play
hope this helps
harpo