right i have downgraded my psp to version 1.5 firstly

i now need help please on installing my ISO correctly, everytime i place it in G/ISO/ it doesnt completely transfer and it says error: due to I/O error or something, also the filename and path cannot be specified sometimes

the USB works because other files work good, also the memory card is 512 and has nothing on it and it was only 300mb ISO game

can anyone help me? ive installed UMD emulator also, my msn is venom164@hotmail.com if anything can please help me