This thread was discussed in German and here is an abbreviated English version.
Problem: When loading some gliders at some locations, i.e. slope soaring sites, like Seiser Alm etc., Aerofly RC7 freezes completely.
Solution: The culprit seems a corrupted config file. This worked for me at least and it may work for you as well in Windows 7 64bit.
Look for the config file of RC 7. In Windows 7 64 bit it is located at Computer --> Local Disk C: --> Libraries --> Documents --> aerofly RC 7 --> config.
Simply delete this config file. Then restart Aerofly RC 7 as usual. RC 7 will automatically re-write a new config file. You now should be back in business.
Hope this helps.