hey guys, i had this problem when using bob's ui, the market explorer window wouldn't open.
i had to relog and switch to atlantis interface inorder to search housing.

anw, ive noticed some other ppl have the same problem so here's how i solved it.

there is a fix published by the developers of bob's right here:
http://bobsui.koamon.com/downloads.html

unfortunatelly this link seems to be dead (or was at the time i was looking for it)

anw, you can still download the file this way:
navigate to your daocdir/ui/custom and run Optionschooser.exe
on the top of the window, click help -> check for updates
in the window that appears, click and download this: [ AddOn_MarketExplorer.zip ]
download, and unzip by merging the folders inside your daocdir/ui/custom

run optionschooser.exe, in the left list, navigate to merchant explorer option and choose the window u want,
double click on the skin u want, close optionschooser and relog your game.

that fixed it for me
hope it helps, if problems, pm me here and ill try to help

Thanks for the solution.

Have you got a link by chance to just the OptionsChooser.exe file? I deleted mine a while back