Odd problem adding a 7th culture in 1.5

Normally, when you double-click on an ai faction city you get the scroll with a lot of question-marks. It always displays defenses and ports though, if they are present.

If i start a campaign as one of the factions that i assigned to my new "steppe" culture and look in a city with a wall or port then it is fine, the building graphic and text open no problem. However if i double-click on a steppe-culture city that belongs to the ai, and that city has either a wall or a port, then the game crashs. If i remove the wall/port from the descr_strat and start up again i can double-click the city no problem.

Just wondering if anyone had come across and soved this problem?