troubleshooting tips ;
1} Clear all temp files & cookies.
2} Reboot & retry.
3} Try a different Browser - IE, FF, and for the real PITAS, Google Chrome.
4} Try a different computer.
5} If none of these work? It's possible you have a conflict with a program, or your ISP server(s).
ALSO - I find after IE/Firefox/and or ROBO updates I have problems with sweeps rendering properly, so I make sure JAVA/ADOBE are updated too, and then they *usually* will work - FYI - it sometimes takes numerous days/reboots until things are normal again.