Can anyone tell me what the error codes -2101D and -2101F mean?

Hello all,

Can anyone tell me what the error codes -2101D and -2101F mean? They appear when i try to do an internet recovery from boot. (which i can only bring up by holding down "D" or "OPTION" key for some reason)

P.S This may be linked to having a folder with question mark on boot. OSX Moutain Lion (unsure of version)

Thanks in advance for any help.