Ok, so the Project Settings they are referring to includes the name of the RSLinx driver (such as AB_DF1-1 or AB_ETH-1) and the network node number of the SLC/PLC.
Here is the catch though......the project setting just might be the settings the programmer used on his/her computer and those settings are not correct for your computer.
For example, maybe the programmer connected to the processor over an ethernet connection using an RSLinx driver called "My_Ethernet". But on your PC, maybe you are connecting through the serial port using a driver named "AB_DF1-1". So when you go to download, the software notices that you are using a different setting and wants to know if that should become the new Project setting.
The answer should be "Yes". You want that setting updated to match how your computer talks to that SLC/PLC.
OG