As ceasar sugested, you will find 2 lines simalar to the ones above, make sure "set lean-users" is set to 1, and that the "unbind msg - hello *msg:hello" line has a # at the begining.
Once this is done, you will need to issue a ".restart" in the partyline.
Note, this setting/mode can be a security risk, check the following setting in the confog file "set default-flags" is set to a the correct flags.
This could provide an attacker a method of gaining access to a bot and taking your channels. You should remove the "p" from the setting, as it provides access to the bot.
As for "/msg <bot> pass <password>" not working. Are you sure, that when you changed your hostname, that it matched a user without a password?