It's not unusual for some scorps to go into a phase of "arrested development" if they have been disturbed at a critical point into their moult...Sometimes excessive heat (35-38C) over an extended period of a few days or a couple of weeks will reinitialize the moult although it's also quite common for said scorpion to never moult and eventually die.....In fact i suspect many problems people get with scorps is by and large due to disturbances.
Scorpions sense the world around them through vibration and in the wild the only vibrations they will usually experience are either from prey or predators with prey giving off a small vibrational image and predators a larger one. Imagine then how it must be for a scorp to register constant "huge" images around it (your footsteps as you walk by it's enclosure, opening and closing doors in the house, bassy music and your general maintenance) .. In a scorps world it must feel as if it surrounded by predators/threats and it's this vibrational disturbance that i think lies at the heart of many scorp problems.
You could try relocating it to the least vibrational spot you can find, increase the heat (both day and night), ensure good ventilation, give it no prey items and then just generally leave it completely alone for a few weeks. Either it'll pull through or it won't.
Incidentally....Some scorps can take months to complete their last moult so it's not all doom and gloom....perhaps your scorp is just waiting for the right conditions in which case you could try a couple of weeks with extra heat, a couple of weeks with extra humidity, a couple of weeks with standard conditions and a couple of weeks with dry colder conditions...maybe one of those periods will be within range enough for your scorp to feel "the time is right" although don't go to extreme...to hot or to cold can also be detrimental.
