Actually, the problem seems to be an extra option mixed in there and out of order in cgamescript. As far as I can tell, in the CreateRandomGirl function, the first option is age, second option adds her to the brothel, third option is whether she's a slave or not, fourth option is undead or not(which does nothing), fifth option is whether she can be a monster, sixth option determines if she was kidnapped.
If I'm reading the code right, in the script function, the first option sets the variable of whether she's kidnapped or not, the second option is added to her age, the third option determines a range for the girl's base age (random 1-X, and the game guarantees at least 17) for the second option to be added to, the fourth determines if she's undead, and the fifth determines if she's human. The script forces the slave option to default, which SHOULD be false.
Try compiling with the changes I've made in the attached file and see how it works for you.
Edit: Note that slave and monster options are still backwards on this version, I didn't think to fix that. See final version, below.
Note also this file breaks the beastiality script, so you might want to use a file comparison tool to copy the changes rather than compile this one directly.