[Q]

Due to the fighter bug I would recommend, that you continue your games with the old Version. The combat balance is just too much shifted in favour of the fighters. However if you start a new game without fighters the Version 1.35 is fine. The error Messages that you get are mostly about errors that you already had with Version 1.30 but you never were aware of it!
And contrary to many others on this forum I had almost no problems with the map editor, which is a fantastic tool IMO.
So in summary if you have enough hard disc space, make two copies of SE IV and upgrade one to Version 1.35.