I would be checking for anything that affects connection to the internet as FTM link and sync and FTM operation in general is constantly sending data back and forward in the background
So things like
Windows and modem firewall settings
Does your anti virus allow FTM.EXE?
Modem settings
ISP arrangements
etc
See also
http://help.ancestry.com/app/answers/detail/a_id/5433/kw/lin...John D