Don't know what happened, my FS2004 crashes in loading since yesterday. It's due to G2d.dll error.
From the avsim forum, it might be some bad BGL files there, but I didn't install any add-on scenery. Then I removed the flightplans and AFD files recently installed, but it didn't help.
The most strange thing: this happens in some airports only, like KATL,VHHH,RCTP,....,that I can't count all.