Destination folder on locked volume - help!

[NewFashion]

I have tried to install the MYOB First Edge software and the Parallels software following an upgrade to Snow Leopard. When I try to install the new software it says destination folder on a locked volume. I have tried dragging and copying the install icon to the Applications folder but I then receive an error message that a folder was specified when a file was required. I don't know what to do next. Anyone know?

 

[Satcomer]

Well did you use the same username when you first setup sharing on the Extreme? Use Airport Utility and make sure it is sharing with your current username.