Did you get it working?
Error Status 7 is usually due to an assert on your ro.bootloader failing, i.e. the bootloader on your phone is not acceptable to the ROM dev(s). Check and make sure that the bootloader you have is acceptable.
I've also heard issues with CWM randomly giving this error erroneously. Whether or not it is in error, I've heard the solution was to switch to TWRP.