YOur nick is showing as still in use because of lag... it can take a while for the server to realize you arent really there. The network you are on prolly has a command for you to ghost/recover the nick. Look in the MOTD that you see while connecting for a help channel name, or look on the networks website.
As for the 10053 error, if you are using winXP, that seems to be common, try disabling xp's firewall and connecting to a port other than 6667. There are a few other things ppl have tried to resolve this, but no one solution fits all. Use the search feature here with 10053 as search term, set it to all forums and expand the date range to ALL.
