Help with copying PS3 ISO via Multimen

Hello, So I have recently got a PS3 and it's jailbreaked and I was told I can download roms and just copy them to PS3. The issue is that I have downloaded Mafia 2 and splitted it up as per FAT32 requirement of file size being 4GB. The first ISO which had a disk icon copied to the PS3ISO folder but the second ISO which has a question mark icon shows operation failed screen randomly at any point of getting copied also when it's copied around 80%. Please tell me if i am missing something and how do I fix this issue. Thank you