First defined the var:
public System.Collections.Hashtable _tableInfo;
Then get the reference:
_tableInfo = GameObject.Find("DO_tableInfo").GetComponent<PlayMakerHashTableProxy>().hashTable;
Then add data:
//Update the tableInfo hash with new data
_tableInfo.Add("tableID", tID);
_tableInfo.Add("numPlayers", tnumPlayers);
_tableInfo.Add("numRuns", tnumOfRuns);
_tableInfo.Add("gameNum", tgameNum);