Hang on a minute, the replies above are all good advice but I'm not so sure they answer the real issues. The OP says "the overload/overheat protection device failed". Every dryer I've seen is arranged such that there is an operating thermostat and a safety "overheat" thermostat. In normal operation the element is turned on and off by the operating thermostat with the mark/space ratio varying during the drying cycle and with other factors such as the airflow. Blocking the outlet reduces the cooling of the element (almost completely!) and normally that just means that the element is on for a very short time and off for a long time, all controlled by the operating thermostat.
The safety (overheat) thermostat is only there at all so that when (if) the operating thermostat fails the dryer doesn't catch fire. It is normally resetable but deliberately designed so that resetting it is non-trivial, like you have to reach around the back of the machine. This tends to make people deal with the underlying problem rather than ignore it.
The OP was told that the safety thermostat had failed and I take that to mean that it had gone open circuit and was not resetable. In my experience both the operating and the safety thermostats are prone to simply falling apart. They are after all in a pretty harsh environment and generally they seem to be built around a flimsy cardboard like material (I know it's not really cardboard but that's what it looks like).
So Jackie, was the dryer working OK up to the point of failure? If it was then your outlet arrangement is probably just fine. Did the repairman replace the cutout or just reset it? If he replaced it because it had actually failed then the outlet arrangement may not be perfect but it can't cause the cutout to *fail* so again your outlet arrangement is not to blame. If he simply reset it then something else caused the dryer to overheat in the first place, maybe a faulty or becoming faulty operating thermostat. I guess the only other consideration is the age of the machine. My experience is that up to say 3 years of daily use I'd be surprised to see a thermostat fall apart. By about 10 years I'd expect to have replaced both thermostats (and the element) at least once.
I hope that helps you to analyse the problem and I'd certainly think hard before going to the effort of making a hole in the wall unless you want one anyway.