I have been working on a secert test

base in Alaska and recently encountered a problem. I have been modifying the AFCAD and adding scenery to Delta Junction/Ft Greeley [Allen AAF], AK, US (PABI). Everything was going fine until the other night. When I started up FS2004 I went in and selected a flight starting at PABI. When I hit "Fly Now" the FS2004 spalsh screen comes up, then after 5 sec FS2004 quits and I am back to the desktop.
I then decided to start a flight at PAED and fly up to PABI. Everything went well until I was about 10 miles from the PABI when then again FS2004 quits and I am back to the desktop.
So I am stumped. I have removed all of the modifications I have made and went back to the default scenery and AFCAD but still No Joy.
Anyone have any ideas?
Thanks in advance.