Exceptions aren't always passed on, making troubleshooting difficult

[pmonks]

In some parts of the code exceptions are caught, but then a brand new exception is thrown without passing on the original causative exception. This makes troubleshooting more difficult.

Here's an example of this kind of thing.

Note: I'm already halfway through fixing this throughout the codebase, and will submit a PR for it shortly. I suspect this should be a fairly easy / low risk change to review and merge in, despite the potentially large number of changes throughout the codebase, but as always would welcome additional pairs of eyes on my rusty Java!