Yours has a "ro" in the mount options. That means read only. You want a "rw", which means read/write. Check to see if it is listed in /etc/fstab. If you have booted the PC with the drive plugged in, then it will create an entry there. If so, check to see if it has the ro option instead of rw.
"The only thing necessary for the triumph of evil is for good men to do nothing." Edmund Burke