ArThuR does address the glaring problem with your script, so that you can now connect to two different servers at the same time. But in the off chance you also wanted to join a second or third channel on either of those two servers, just separate the channel names with a comma.

server    SavedGroup  -j #mirc,#irchelp,#chat
server -m -j #politics,#computers

If you want different nicknames on each server, include the -i switch.

server    SavedGroup  -j #mirc,#irchelp,#chat -i Rob Rob- robert@noemail My Name is Robert
server -m -j #politics,#computers -i Bob Bob` bob@noemail My Name is Bobert

If you save your servers into mIRC's server list, grouping them by network name, you can also store additional settings like NickServ login password. In the above examples, SavedGroup references a saved server group.

You currently cannot store a chosen nickname for a server in mIRC's saved servers, so that's where the -i switch comes in handy above.
-i $mnick $anick $email $fullname

Well. At least I won lunch.
Good philosophy, see good in bad, I like!