Can I get some help rooting and flashing a Tab2?

[sagent3000]

Problems rooting and flashing tab2

I attempted to root my Galaxy tab 2 10.1 but i am not sure i did it right

when i try to install "omni-4.4.4.zip

#Manual Mode#
Applying Multi-CSC
Applied the CSC code ATT
Successfully applied multi-csc

then i get

E: failed to verify whole-file signature
E: signature verification failed
Installation aborted

my Clockworkmod recovery us system 3e
the options i have are
- reboot system
- apply update from external storage
- wipe data
- wipe cache partition
- apply update from cache

i am running 4.1.2
baseband version - I497UCMF2
kernel - 3.0.31 - 1218964
Build number - JZO54K-I497UCBMF2

anyone know how to fix this problem? i have reflashed the 3 times using odin 3 and the file CF-Auto-Root-espresso10att-espresso10uc-samsungsghi497.tar.md5