The second EXECUTE has a missing closing parenthesis.

However, why do you go this complicated EXECUTE way?
Code:

$UnicodeUsername=''
for $pos=1 to len($username)
  $UnicodeUsername=$UnicodeUsername+dectohex(asc(substr($username,$pos,1)))+'00'
next
? $username
? $unicodeusername
_________________________
There are two types of vessels, submarines and targets.