When you use tokenat to parse text from a file, the resulting string may start with an empty line. That's why the text is invisible - you see empty lines and don't see the rest of the text.
So you need to use trim() expression to remove all empty lines from the beginning and end of the string.
Also, don't use round() with random, if you need a random number from 0 to 9, the correct expression is int(random(0,10))