I need to know if problems can arise about my old debt when I buy
Much more information is needed, and a clear understaning of the law of the state where the foreclosur occurred and the law of the state where you will be buying the new home. It may be that the law of the state where the freclosure occurred does not permit deficiency judgments or it may be to long now after the fact. for them to pursue a deficiency. However, if they already have a deficiency judgment or can still get one, then the other part of the equation is whether the law in yoru current state would protect the equity in the new home from the clains of creditors or not.
Please note that I do not practice in your state and that the above is not intended as legal advice, it is for educational purposes only. No attorney-client relationship is created or is intended to be created hereby. You should contact a local attorney to discuss and to obtain legal advice.