problems with timthumb in subdirectory

i have an open house theme, with the timthumb script.

with a wordpress instalation in my root or subdomain timhumb works.

http://www.bulgariaprimeproperties.com
nl.bulgariaprimeproperties.com

but if i put in in a subfolder, timthumb refuses to work.

http://www.bulgariaprimeproperties.com/nederlands

http://www.bulgariaprimeproperties.com/nederlands/wp-content/themes/backup/Openhouse_Multilingual/scripts/timthumb.php

timthumb itself works, because it says no image specified.

how can i make this work, is this the secuirity issue from timthumb?? how can i rewire it?