Can i get rejected from an immigration visa petition?

I live in bangladesh.my brother applied for our immigration under the f4 catagory in 1999.they approved our case in 2002 and sent to the local processing centre for further processing.we didnt fake a single information.but still is their any chance that our application might get rejected?? We also won dv in 2003 but got rejected bec my degree certificate had my family name in it but i didnt applied for dv with my family name.can something like that happen in this case?? Oh and by the way how much do we have to wait untill our priority dates are available?please help me.