In this case, $gettok(%line,5,32) is returning the set of characters between the 4th and 5th space characters.
If you know that the character you don't want is the / character, then you could do a 2nd $gettok to handle that character.
Here's your code with that change.
on *:text:*:#:{
var %line = $strip($1-,burc)
var %text = $gettok(%line,5,32)
var %text = $gettok(%text,-1,47)
echo -a %text
}
and here is another re-write using some more token functions.. it's a bit more advanced than what you have.
on *:text:*:#:{
tokenize 32 $strip($1-)
var %text = $gettok($5,-1,47)
echo -a %text
}