well , I maybe found the problem. In ubbt 7.2 , it needs a "1.php" located in styles/ directory. But after installed , there's no such a file.
After I copy from 7.1 and related css files to here, it works.
English is not my native language. I try my best to express my thought precisely. I hope you understand what I mean. If any misunderstanding results from culture gaps, I apologize first.
