Would help if you were a wee bit more descriptive. Does 'didn't work' mean it did something wrong? Or didn't change anything? Didn't output anything? etc?
First, it would help with scripts so that any time you call an identifier that doesn't exist, that it halts the script with an error to status window instead of treating the identifier call as returning $null. That way you know that 'no output' is because of your scripting error to $no_such_identifier, and not because of the identifier not working right.
To do this, simply pull open the 'options' dropdown in the remote script editor and make sure 'identifier warning' is checked.
Assuming your existing code already works, and assuming you added these aliases as I explained, it should work to fix the line
set %radiotest.song $gettok($regml(1),7-,44)
and editing it to become
set %radiotest.song $html2ascii( $gettok($regml(1),7-,44) )
... though actually the way your code works, you do not need this to be a global variable, so you can create this as a local variable using var instead of set. But it should work fine both ways.