It appears that both versions of the tool have a bug in the default conversions defined in NativeMappings.hs
They got introduced in a major restructuring that took place before 4.8 and slipped through my regression tests.
I’ll upload a fixed version as soon as possible.
Sorry for any inconvenience
Update: Version 0.5.1 fixes the bug mentioned.
Some more details: originally all my convertion functions were pure, the problem is, some activities like creating a pointer required IO. This is why currently everything is done in IO. When I converted the library I missed some calls, and those calls were giving an error now saying that the convertion function was undefined.