This is a 2008 not 2008R2--it is a VM on Hyper-V 2012. I have run all the required adprep on the 2003 Domain controller. Error5 I get is "access denied" for trying to join to the 20003 domain. I am attaching a word document with a series of screenshots that I took on my third attempt at this--I have added comments on top of each picture/screenshot for added explanations. As an added FYI, thinking maybe I was doing something wrong, I went to another client's 2012 Hyper-V, added a 2008 server, and without any issues was able to successfully join it to their 2003 domain; this leads me to conclude there is some issue on this 2003 domain that is preventing me from joining to it but I don't know what else to try.
Followed these directions w/o any resolution https://support.microsoft.com/en-us/kb/2002413/en-gb