FSX Lockups

FSX LockupsI'm experiencing frequent, but random lockups, when starting FSX while converting scenery to FSX. The lockups occur after selecting a saved flight in the location of the scenery being converted at the screen "Loading Scenery Objects". If I get a lockup, restarting FSX and trying again may succeed, or it may not, and I may have to try several times to succeed. It seems most lockups occur after generating a new GMAX object, but because of the randomness of the lockups I am not sure.I never have lockups with FS9 or FSX after successfully starting it.I don't have lockups if I create a new flight in the conversion area.I never have lockups with any of the Microsoft scenery areas, only my own scenery area being converted. This seems to eliminate a hardware problem such as overheating. My PC is not overclocked.The scenery being converted to GMAX consists of a lot of SCASM objects that don't show correctly. I am not using the latest SDK GMAX or BGLCOMP to compile the GMAX objects. They show correctly.I would like to know if others have this problem and if any of the info above suggest a known cause of the lockups.The randomness of the lockups is very puzzling and is terribly frustrating since load times are so long. I wonder if it is an FSX bug.Thanks, Jim JonesMicron P4 2.8GHz 533FSB 512k cache2.0 Gb DDR SDRAM2x120GB ATA-100 IDE Hard Drives (7200 RPM)128 Mb DDR nVidia Geforce4 TI4600 (BIOS Aperature Set to 128 MB)Seagate 400 GB 7200RPM External USB Drive - 16Mb CacheCreative Labs Sound Blaster Live!Original Drivers ( 6.14.10.6177 ) plus stereo driversPioneer DVD-RW DVR-104 Direct X 9.0cWindows XP with SP1 & SP2