Yeah, first thing I thought was whether you had some text in that paragraph. I make that mistake ALL the time . Either that or make sure that the text is visible (i.e. not showing a bunch of empty lines while the real text is outside the string's area).
You could post the file somewhere if you still couldn't figure it out...
Disclaimer: Any sarcasm in my posts will not be mentioned as that would ruin the purpose. It is assumed that the reader is intelligent enough to tell the difference between what is sarcasm and what is not.
1. Open level editor
2. Find text object (which is usually in some distant corner of the enormous playfield)
3. Edit text object
4. Insert paragraphs in stupid editor
5. Return to event editor
6. Insert the event that changes the paragraph
...when I could just as well had used a single event to change the alterable string to whatever I want it to be.