Hello! Im Sofia from BA Argentina and since Im planning on travelling to the US just for a week for vacation, I checked my passports. But to my surprise, I noticed that an officer sometime in one of my several trips Ive done to the US a few years ago, has wrote CWOP on my B1 (Turist) visa. What does this mean? Would I have any problem with this? My visa expires in 2012. But I'm veru concerned about it and id like to avoid getting another visa if I already got one and its still useful.Thanks!!

CWOP is "cancelled without prejudice" this indicates the visa has been cancelled, but no derogatory information, so you should not have a problem applying for another visa.