Okay.. I've done a LOT more digging and reading through the forum and yellow's website PRAYING to find a clue..
After some more investigation, and testing it appears that the heart of the issue isn't with either of these mods at all. The issue is that the login is redirecting to a page that SSU says does not exist.. and TECHNICALLY it does not..
So here's what I did.. I turned off SSU and tried to log in to the store..
Upon logging me in, I am redirected to the following page:
http://clients.overthehillweb.com/ha...isleflash2_swf=
Which is STRANGE as heck 'cause I don't know where that URL is coming from.. With SSU off, this URL displays the main site page. However, it does provide some insight at to why SSU hiccups. If SSU attempts to make this link SEO friendly you get this:
http://clients.overthehillweb.com/ha...isleflash2_swf
Which is exactly what happens when you login with SSU on and Zen Cart tells me that this page cannot be found.. (It's not a real page, so this makes sense too..)
So the last thing I did was to remove the .htaccess file, and see if the login behavior went back to normal and it did. So after all of this I am guessing that the issue is in my .htaccess file, and here's where my eyes start to CROSS.. 
What on earth to I need to add, subtract, or divide from my .htaccess file to get this to redirect the login correctly..
Contents of my .htaccess file
Code:
#### BOF SSU
Options +FollowSymLinks -MultiViews
RewriteEngine On
# Make sure to change "zencart" to the subfolder you install ZC. If you use root folder, change to: RewriteBase /
RewriteBase /hairisle/
# Deny access from .htaccess
RewriteRule ^\.htaccess$ - [F]
RewriteCond %{SCRIPT_FILENAME} !-f
RewriteCond %{SCRIPT_FILENAME} !-d
RewriteRule ^(.*) index.php?/$1 [E=VAR1:$1,QSA,L]
#### EOF SSU
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