try reboot your router or network connection and
Reboot your PC (Don't just log out and login)
That's how I solve the same problem as yours , not encounter this problem long time ago.
Better run SSF4 AE with a new boot, I think it is a way to avoid the PC crash or the SF game crash during game play.
I think a clean memory space for that game may assure a more stable game play experience.
I've exp 2 or 3 time after winning a rank match, just keep pushing the start button then cause a crash, then lose the BP and PP.......