It would have been a good idea to post this report in the tool's main thread.
I almost missed this.
Without your problem SKP itself, then who can tell what's actually happening?
Is it failing on every SKP or one in particular ?
How does it 'crash' ?
e.g. it hangs, it bugsplat, it shows a zero volume result ?
It works fine for me.
It is possible to devise two solids which when one is subtracted produces a non-solid.
Since the API uses the Solid-tools as a basis, please try doing a manual subtraction of one from the other - make a copy of the two solids beforehand and also do the opposite subtraction if the first succeeds. There might be some tiny difference in the volumes creating ultra-thin slivers in the subtractions, thereby causing issues ??
Do you still have v2 to retry ?
The licensing regime doesn't change with version.
So reinstalling v2 over v3 will probably work ?