Hi, My sources tell me that this is a common fault with this model, probably due to the complicated clockwork winding mechanism. I'm not sure if it can be repaired. The camera, as it is, has a value of about $50, so its probably not worth spending money to get it repaired - if you could find anyone to do it.
Can you perhaps give more information on what is happening? The take up spool is the powered part, and if that rotates properly then the film pulls the sprockets,(they don't pull the film), and un-latches the shutter release.
Many seemingly "simple to load in theory" cameras are in fact odd in operation and must be used strictly to the way the designer intended.
All the earlier Finetta did something very drastic, they have no sprocket at all, the spacing was done by the take up spool, and was therefore variable along the length of the film. this annoyed Kodak deeply, as it made cutting up slides difficult.
Finetta did this to reduce cost, it eliminated an entire mechanism from the camera.
The Finetta 99 went the opposite way, it was more complex in having the clockwork motor, and it has the sprocket drive to exactly evenly space the frames.
I am making assumptions about the Finetta somewhat, as I have not got one to hand at present, but any of the type of drives where the take up spool pulls the film, and drags the sprockets with the film, are usually a type that needs the film in place to operate.
Reliability was not good on Finetta, the cost of developing the camera bankrupted Saraber, and many small design issues were never sorted out.
The Robot, which is also clockwork delivers the film via the powered sprocket only the take up reel is only there to take up slack.