Heretic,
Your response was very helpful. I downloaded the Compiler/Decompiler program, and it is very easy to use. However, when the program checked the FS9 flight plan it found an error in one leg of a flight with a wrong airport elevation. Because of the error it would not complete the process. Therefore I will need to locate the error in a very long string of numbers.
Additional comments:
I could not find the elevation error in the FS9 flight plans. So I had the program decompile the FSX VHHX blg flight plans that I had downloaded from the Internet. I deleted the VHHH airport in the airport txt file, then I added the correct coordinance for the Fly Tampa's Kai Tak airport, VHHX. Then I opened in Notepad the txt VHHX flight plans and had the edit file find and replace VHHH to VHHX. I then recompiled the three txt files back into the FSX VHHX blg file. And when I started up FSX and loaded the VHHX airport it was filled with aircraft.
The following images show the VHHX airport populated with aircraft.


Once again, thank you Heretic for directing me to the Compiler/Decompiler program. The nice thing about the program is that it works with both FS9 and FSX blg files, whereas TTools only works with FS9.
Wired