First you said
I want to be able to enter a client w/o having to enter a domain or pick one from the list first.
Then you said one paragraph later
I just want to be able to select from the list in the combo box, which is bound to the Domain Information table, AND be able to type new domain names in the combo box and have that entry update the Domain Information Table with a new domain name.
You need to decide how the form will be used before you can build it or I quite cannot understand what you are after but It seems like your input forms are in a vicious circle both waiting for the other one to get data. Anyway I took another shot at it, take a look if its not what you want put some data in there to show what your trying to obtain and send it back.
You should try not to use spaces in you Database Object Names as it makes it really complex later if you have to seperate a Table / Textbox / Anything name use the under_score