In my first example I used "term" in the following way: provisions that determine the nature and scope of an agreement. In this way it would mean that the countries had equal (but no necessarily the same) views regarding the conditions of a defense agreement. In my second example I used "term" in this way: mutual relationship : footing <on good terms>. In this way it would mean that we have an equal relationship one negotiating party is not superior to the other.
In your sentences: "a) Tom is wealthy, but he doesn't mind to make friends with those background are not in equal terms with him."
I think this would be better stated as follows: Tom is wealthy, but he makes friends with anyone regardless of their economic status.
In your last sentence: "I am in equal terms with Jo upon discussing the handling of the current financial problem."
I think it would be better stated as follows: "Jo and I are on equal terms in discussing the handling of the current financial problem." ;-)