The game I have was not GOW Chain of Olympus and Ghost of Sparta (PSP Game conversion) but this is rip game from GOW collection (GOW I and II). The uploader upload the file not in separate pkg, but in complete 5.88GB pkg file..
If it is a psn game released from duplex, I suggest you to transfer it into hard disk of ps3 via ftp server.
He needs to get the path, where he has to transfer it, to install the *.PKG. I just remember that DUPLEX wrote it should be transferred to an FAT32 formatted Device - which can be tricky for an 5,88GB file.