Using VMWARE for FSX and the 777 is not your answer. The best way to run FDSX and the 777 is using a Bootcamp partition. That is the way I have my iMac setup and it works as perfectly &@($* FSX will allow.
The 777 freezing drove me crazy as well. here is the fix:
1. Navigate in Windows to C:\Users\Yourusername\My Documents\Flight Simulator X Files\
2. Find the file logbook.bin
3. rename to logbook.bin file to logbook.old
4. Restart FSX and FSX will now create a new logbook.bin file and no more freezing.
Works perfectly