ans what if $1- contain a '^' :) ? The same problem exist with his $chr(96) anyway but this already has been said.
What hasn't:
-you are using sockwrite -n even when -n isn't necessary with this super-useless tokenize command.
-there's no point in making (trying to make actually) everything possible not to get the same socket name if at the end, if the same socket name is used (it's possible), you'll close the socket, why not just var %b = $sock(bw,0) + 1,%name = bw $+ %b | sockopen %name for example?
-checking if the socket is opened before closing it because you're going to open isn't necessary, just close it, mirc handle the fact that is doesn't exist for you
-you should have one connection and keep it alive, then use it for each new request, that would avoid the opening of the connection (= much faster)
-Using unset %1 is not really a safe thing to do.

That script is unusable as it is anyway, it would freeze mirc depending on the size of the text file and the activity of the channel..