User read & write permissions greyed out in sharing

Hi I am trying to access a Fat32 formatted HD plugged into a Macbook running lion from a Macbook Pro running Mavericks. When i go into system preferences and sharing I am able to see the External HD and share it but the read and write options for the users are all greyed out. Also when I access the macbook through sharing or connect to server I am unable to see the external HD but I do see the other shared folders on the macbook's internal drive. I have tried to verify and repair the drive but it has not solved the problem. Any suggestions would be greatly appreciated.