I may have identified the problem code outside of zencart. I used the timestamp and ip address in the admin logs to locate the access logs on the old server. It appears that the hacker was executing a php script from a folder outside of zencart. Here are the access log entries. If you could verify that this in fact is what they used to access the cart I'd appreciate it.
115.90.96.85 - - [11/Dec/2012:09:28:27 -0500] "GET /gfsdgfdsg/ HTTP/1.1" 200 - https://www.sweetsouls.com "-" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:28:28 -0500] "GET /gfsdgfdsg/login.php?camefrom=index.php HTTP/1.1" 200 2172 https://www.sweetsouls.com "-" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:28:47 -0500] "POST /myfiles/media/a_(1).php5 HTTP/1.1" 200 1836 https://www.sweetsouls.com "http://www.sweetsouls.com" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)" "109.129.224.142"
115.90.96.85 - - [11/Dec/2012:09:29:00 -0500] "POST /gfsdgfdsg/login.php?camefrom=index.php HTTP/1.1" 200 2223 https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/login.php?camefrom=index.php" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:29:11 -0500] "POST /myfiles/media/a_(1).php5 HTTP/1.1" 200 223 https://www.sweetsouls.com "http://www.sweetsouls.com" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)" "109.129.224.142"
115.90.96.85 - - [11/Dec/2012:09:29:13 -0500] "POST /myfiles/media/a_(1).php5 HTTP/1.1" 200 1878 https://www.sweetsouls.com "http://www.sweetsouls.com" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)" "109.129.224.142"
115.90.96.85 - - [11/Dec/2012:09:29:27 -0500] "POST /myfiles/media/a_(1).php5 HTTP/1.1" 200 647 https://www.sweetsouls.com "http://www.sweetsouls.com" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)" "109.129.224.142"
115.90.96.85 - - [11/Dec/2012:09:29:35 -0500] "POST /myfiles/media/a_(1).php5 HTTP/1.1" 200 1237 https://www.sweetsouls.com "http://www.sweetsouls.com" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)" "109.129.224.142"
115.90.96.85 - - [11/Dec/2012:09:52:06 -0500] "POST /gfsdgfdsg/login.php?camefrom=index.php HTTP/1.1" 200 - https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/login.php?camefrom=index.php" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:52:06 -0500] "GET /gfsdgfdsg/index.php HTTP/1.1" 200 - https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/login.php?camefrom=index.php" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:52:07 -0500] "GET /gfsdgfdsg/login.php?camefrom=index.php HTTP/1.1" 200 2172 https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/login.php?camefrom=index.php" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:52:22 -0500] "POST /gfsdgfdsg/login.php?camefrom=index.php HTTP/1.1" 200 - https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/login.php?camefrom=index.php" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:52:22 -0500] "GET /gfsdgfdsg/index.php HTTP/1.1" 200 22791 https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/login.php?camefrom=index.php" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:52:28 -0500] "GET /gfsdgfdsg/modules.php?set=payment HTTP/1.1" 200 26937 https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/index.php" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:52:32 -0500] "GET /gfsdgfdsg/modules.php?set=payment&module=paypal HTTP/1.1" 200 29193 https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/modules.php?set=payment" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:52:39 -0500] "GET /gfsdgfdsg/modules.php?set=payment&module=paypal&action=edit HTTP/1.1" 200 41991 https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/modules.php?set=payment&module=paypal" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:52:51 -0500] "POST /gfsdgfdsg/modules.php?set=payment&module=paypal&action=save HTTP/1.1" 200 - https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/modules.php?set=payment&module=paypal&action=edit" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"
115.90.96.85 - - [11/Dec/2012:09:52:54 -0500] "GET /gfsdgfdsg/modules.php?set=payment&module=paypal HTTP/1.1" 200 29193 https://www.sweetsouls.com "http://www.sweetsouls.com/gfsdgfdsg/modules.php?set=payment&module=paypal&action=edit" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5" "-"