In my experience, lock ups in trying to enter the slave market are due to girls with incompatibilities in the .girlsx files. What I usually do in that case is to use the editor, load the file and go through the girls individually. I forget when the error pops up, (either when you first click on a broken girl, or when you try to save her stats) but when you find a girl that pops up an error message, just go in and fix her stats (most of the time, I believe it was due to dashes [-] in the stats area, rather than numbers) and then MAKE SURE TO CHOOSE *UPDATE SELECTED*, then save the .girlsx file. If you fix all the mucked up stats, the slave market should load fine and not crash the game.