I think I found your problem.
Code:
IF userid = Peter THEN
PRINT "Please enter your password to continue."
ELSEIF userid = Peteriscool THEN
This needs to be:
Code:
IF userid = "Peter" THEN
PRINT "Please enter your password to continue."
ELSEIF userid = "Peteriscool" THEN
Since you defined userid as a string, all possible values have to be in quotes.
Hope that helps some.