Most servo motors will have thermal switches in them that will cut out if they get too hot, assuming of course your servo drives support such an option. Most industrial rated drives do but I dont know what you have.
Regarding losing position, if that is the case then I would say your following error value is set too high, again whether you have the ability to alter that will depend on what drives you have, the cheaper hobby end ones likely wont have too many options.
Hood