Fail error with Odin, how can I fix it?

[mrtgman23]

Fail error with Odin

I have been trying to downgrade from 5.0.1 and have been getting a fail error. I have followed the instructions but still get the following error. Can anyone help? Thanks.

ID:0/004> Added!!
<ID:0/004> Removed!!
<ID:0/007> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> I545VRUEMJ7_I545VZWEMJ7_I545VRUEMJ7_HOME.tar.md5 is valid.
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/007> Odin v.3 engine (ID:7)..
<ID:0/007> File analysis..
<ID:0/007> SetupConnection..
<ID:0/007> Initialzation..
<ID:0/007> Get PIT for mapping..
<ID:0/007> Firmware update start..
<ID:0/007> SingleDownload.
<ID:0/007> sbl2.mbn
<ID:0/007> NAND Write Start!!
<ID:0/007> sbl3.mbn
<ID:0/007> rpm.mbn
<ID:0/007> aboot.mbn
<ID:0/007> FAIL! (Auth)
<ID:0/007>
<ID:0/007> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)