Melissa, You've got a mystery on your hands! I couldn't find a Charles Prokopovic on the Ellis Island Records website, but I did find a Charles Prokop. There's not much information about him. I would say that Charles is a very unusual name for a Slovak or Ruthenian/Rusyn. Andras,Jan,Georgy and Mihaly were the majority of first names that I found being used by these ethnic groups. Have you gotten a death record? If you know where and when he died,then get his death record from that town.His death record should give you where and when he was born, and his parents' names. He might have applied for citezenship. If so, you can check for "a Declaration of Intention" in a city,town, or county court records. Our local country historian has copies of these records for Oswego Co, NY. I found my husband's Italian records this way. Our historian (and some Fun. Homes) also has Funeral Home records which sometimes have good information. How's about a Soc. Sec. record? Go to the SSDI website for that. Hmmm...that's all the ideas I have for now. Good luck!