Owner financing is most times at a higher interest rate than banks, credit unions, and others in the business of lending money for mortgages. Many, if not all, owners would also want to have credit reports on the buyer/borrower run. If your credit reports and resulting FICO scores are the cause of the high rates lenders want you to pay for a mortgage, a private seller will also probably want even higher rates than the banks after getting your credit report.
It appears from your second email that your name is still on the mortgage for the house that your ex-wife got in the divorce and you are being penalized because she is making late payments. You might want to check the divorce paperwork to see whether she was required to get a mortgage in her name alone in exhange for getting 100% title to the house. I'd also suggest that you contact the attorney who handled your divorce, or another attorney who specializes in divorce work or real estate, to see if there is any way you can be removed from the mortgage.
I also suggest that you get a copy of your credit report from all 3 credit reporting agencies (this booklet from the federal government tells you how to get the copies. You should request than any mistakes in your credit reports be investigated and corrected. Here's how to do this: http://www.pueblo.gsa.gov/cic_text/money/fair-credit/fair-crd.htm
If you ex's late payments are continuing to adversely affect your credit after you've consulted with an attorney to get the legal situation regarding who is reponsible for making the mortgage payments straighted out and checked all credit reports for errors and had the errorts corrected, try to have a written statement added to each of the credit reports regarding the situation.
Also, I have a brochure on my website that has quite a bit of information that may help you improve our chances of getting a mortgage at terms you will find acceptable. http://maryhester.com/images/consumer%20credit%20handbook.pdf
Finally, the bigger the down payment you can make, will probably increase your chances of getting acceptable mortgage terms.
Good luck. When you're ready, feel free to use my website to search for homes in the MLS.