well the 'echo' is wrong.
most mirc commands u are typing and get an error the command will /halt.
so if u want to echo something to the ACTIVE window do /echo -a 123
or /echo -a 456
but don't do /echo 123 becuz the First parameter of the echo command is a color, u typed a number so mirc thought its a color number and then he get the error becuz u didn't spcified any text, anyway use -a switch for active window