YOUR ON TEXT events do not trigger when YOU type text, they go off when other people type text, use a second instance of mirc to test this out in.

Ps: / and // are not needed inside script files as it is taken as granted that all lines encountered are commands etc and its also assumed that you want to evaluate all variables and identifiers (ie: //)

Pss : the //echo well display the literal text "//echo" since it is just text being sent inside a MSG command