you could prolly be on DALnet ..
if you are then you need a registered nick to get into that channel type the following preferably in your status window .....
/nickserv register password your`valid`email
after which carefully read the msg/notice from NickServ to you and follow it from then ..
once registered fully . identify to your nick using ...
/ns identify password
after which you would have an identified/registered nick so you can enter that channel