Pass the "-CONT_PATH" (container path) argument via the "cmd_line" variable (the Hashtable).
e.g.
String containerPath = "/wt.inf.container.OrgContainer=Org1/wt.pdmlink.PDMLinkProduct=Test Product";
Hashtable cmd_line = new Hashtable();
cmd_line.put("-CONT_PATH", containerPath);
LoadFromFile.doFileLoad(filepath, null, null, null, cmd_line);