Help with downgrading to android 4.4.4 on SM-G900V?

To start out, I will say that I am not the best with this kind of stuff and do not know THAT much about rooting/flashing ROMs and what not. I have read many posts about how to go about doing this and here is what I tried. I downloaded Odin 3.11.1 and the most recent Android 4.4.4 version (USA) from SamMobile. I turned my phone off and put it into download mode. After this, I started Odin, and pressed VOL up on my device to continue. Odin said "Added". I selected the file to flash in the AP section (G900VVRU1ANK2_G900VVZW1ANK2_G900VVRU1ANK2_HOME.ta r.md5) and hit start. This is what came up in Odin:

<ID:0/006> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/006> Odin engine v(ID:3.1101)..
<ID:0/006> File analysis..
<ID:0/006> SetupConnection..
<ID:0/006> Initialzation..
<ID:0/006> Get PIT for mapping..
<ID:0/006> Firmware update start..
<ID:0/006> SingleDownload.
<ID:0/006> aboot.mbn
<ID:0/006> NAND Write Start!!
<ID:0/006> FAIL! (Auth)
<ID:0/006>
<ID:0/006> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

I have tried this many times with all the USB slots on my PC and with 3 different cords. I have also tried different versions of Odin. I'm not sure if any of that would change anything, like I said, I do not really know what I am doing. Am I doing something wrong here? Any help is greatly appreciated! Thanks, Hunter.