I have a similar problem with a 10 year old MiniDV camcorder made by Sony. It is because of improper operation of electrical contact pads in a rotating mechanical switch.
The camcorder tape mechanism is controlled by a motor that rotates through all operations: Eject, Play, Stop, Fast Forward, Rewind. The rotating mechanical switch tells the computer which one one of these functions is currently active, and which way the mechanism motor needs to turn, to get to the next function.
The computer is getting incorrect signals from the position encoder switch and so it doesn't know the current position of the tape mechanism. It either tries to move to the Eject position, or it already thinks it is in the Eject position but actually isn't so it won't move the mechanism to eject.
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The camera failure seems to be caused by lubricating grease that hardens and turns into slime, and then prevents proper electrical contact of spring contact fingers in the rotating switch.
The solution is to take apart the camera, open up this rotating switch, and then dissolve the grease with something like rubbing alcohol. Either apply fresh grease, or just forget about it and put it back together without any grease.
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Except. Well. The camera components are all so tiny that taking it apart is an extremely difficult and delicate process, and you have no service manual so you are stuck guessing as to how to take it apart without destroying it.
And if you've got a tape stuck in it, it's all that much harder because there may be no way to take it apart without the tape door already open and the tape removed.
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Though there is sometimes a secret way to make it eject anyway. The door latch is usually spring operated, and so sometimes it is possible to slap the camera hard enough in a certain way to cause the release latch to pop open without damaging the tape or the mechanism.
It might also be possible to fit a very thin plastic or metal feeler or "spudger" into the gap of the door and manually push the door latch open.
