I may be able to offer some advice in spite of things
tonight.
You mention a Civil claims Judgment. It appears to me that you are looking at only your credit reports. The only way to know for sure is to check with the county clerk where you lived before leaving the country. It may say what jurisdiction it is in on your credit report (I have a judgment, it is not on my reports). If it is a REAL judgment, they must have proper service for it to be a valid judgment. That would be a defense to get it vacated. Consult an attorney.
Statute of Limitations (SOL) varies from state to state, and can be found in your state's Rules of Civil Procedure. I believe we have a thread here with that info.
There are things you can do to help yourself. One is strategic disputes, but do NOT dispute as "not mine." If you do have a judgment, you can possibly dispute it and get it off your report, but you can't buy property in the county where it is filed without it haunting you.
Find out about the judgment from the county clerk (may be available on line). Get back with us.