When you encounter this error, then the thing you will need to do is to copy the contents of the both discs right into a folder of your choice and then run the setup package from that location. This happens because the installer has not been properly configured by the developer. Apparently, you are not the only user who encounters this error. Make sure that when you perform the copy operation, you put together all the files from the discs so the setup should know where to get the next volume from.