Try compressing (zipping) your EFI before uploading.
Are you certain that the config.plist you attached is on your boot volume and is the one that OC is loading? The 'bootprotect at 5 index' error you posted would occur if you still had bootprotect in your config.plist's Misc>Security block (which would have been in a config.plist prior to OC 0.6.6).
@henryrym - I suspect that the config.plist you uploaded is not your current config.plist. The config.plist you uploaded still includes "No-hda-gfx" in DeviceProperties (the property you said you removed when trying to get sound to work). Just upload your complete EFI (with sanitized PlatformInfo>Generic>MLB,SystemSerialNumber,SystemUUID) and we can take a look.