[plt-scheme] Depth first search critique?

Hello everyone,
	Would anyone care to critique my code? Would it be terrible to  
submit it here for critique?
	I'm taking an AI class and we're allowed to submit our homework in  
any language available on our computing system. Seemed like a great  
opportunity to get back into scheme.
	So, I've got some working code for depth-limited search and  
iterative-deepening search. I'd just like to know how to improve my  
style, though serious performance issues would be good to know about.

Joseph Holsten