In general, no you don't need to get permission.
In MRPS case they want to ensure pictures are not being sold, so they want permission to be gotten before posting. If a place expects that kind of thing, I would hope they would make it LOUD and CLEAR. MPRS did make it loud and clear.
I can't wait to see you post your stuff here!! I need to look into an audio upload thingee... I wonder if my paid account has anything?