For yery corrupted collada files, there appears just a messagebox "import failed [OK]". The ruby console does not display any exception but just true``.
For some collada files, SketchUp says there is a chance that the import could fail and asks if I want to continue [yes]/[no].
If I click yes, it succeeds to import it anyways, if I click no, the same messagebox appears "import failed [Ok]. In all cases, the console says true. I tried it with begin ... rescue ... end without success.
model.zip