Unable to flash MIUI

[Omga4000]

Hey guys

I've been trying to install MIUI for hours, using both CWM or TWRP, and I'm always receiving the same error message:
set-perm: some changes failed
E:Error in /sdcard/miui_i9500_4.6.20_27061504e7_4.2.zip
(Status 7)
Installation aborted

I've flashed CM without a problem, and an original stock ROM as well.
Why is MIUI giving me a hard time?

I tried deleting the "assert" code, but yields the same results.

Thank you!