You have:
Code:
SetText(gInstructions "You are about to take part in an experiment that involves gambling with play money. You will start with a $2000 loan. On each trial, you will select a card from one of four decks, by clicking with the mouse. After you select each card, you will be given a reward and possibly be required to pay a penalty. Your goal is to maximize the profit on your loan, and you may choose from any deck at any time to do so.
Do you have any questions?
Press any key to begin.")
There are a bunch of new lines in your string, and that's not allowed. Use the "\n" (backslash n) newline notation instead:
Code:
SetText(gInstructions "You are about to take part in an experiment that involves gambling with play money. You will start with a $2000 loan. On each trial, you will select a card from one of four decks, by clicking with the mouse. After you select each card, you will be given a reward and possibly be required to pay a penalty. Your goal is to maximize the profit on your loan, and you may choose from any deck at any time to do so.\n\nDo you have any questions?\n\n\nPress any key to begin.")
Of course, you should really split this message up over a number of lines.