Comments should be fine as long as they are outside the #selectmonster and #end. I use them all the time in my mods
The reason you are getting more crashes is because of the other problem I found with the mod. Dominions will not accept the resource value for a monster at 1000. That is why it was giving the error message "bad monres". I reduced all the resource values to 800 and the mod works perfect, loads turns etc etc.
It is a bit annoying to have to rewrite a mod because someone did not test before they posted it!
Be sure to atleast play the mod once before posting it for others to use!