We discovered this with a customer yesterday. DNS resolving (using `Resolv::DNS#getaddresses`) failed. It turned out that the underlying problem was that the way `win32/registry.rb` retrieves error messages from Windows is flawed, under certain circumstances.

The bug only appears if:

- `JAVA_OPTS` includes `-Dfile.encoding=UTF-8`
- The environment you run it on is a _non-English_ Windows installation, or more specifically: a Windows installation where the error message(s) include some non-ASCII character. The specific use case here is a Swedish Windows installation, where the error message for error number 2 (File not found) reads as "Filen du söker finns inte", or something similar. (The debugging here was complicated by the fact that I don't have a Swedish Windows myself, only the customer).

Here is a test script that reproduces the problem given that you have a Swedish Windows:

```ruby

require 'win32/resolv'
puts Encoding.locale_charmap
puts Win32::Resolv.send(:get_info).inspect
```

Since I don't have a Swedish Windows, I managed to reproduce the same error locally by adding this code into the `Error` constructor:

```ruby
msg = "Malm\xf6, G\xf6teborg och V\xe4xj\xf6"
```

That gives me the same error: `ArgumentError: invalid byte sequence in UTF-8`. The original bug occurs in the `msg.tr` call, since the string it operates on is _marked_ as UTF-8 (because of the `force_encoding` call), where it is in fact Windows-1252 encoded (since we call `FormatMessageA`, which returns Windows-1252 encoded strings...). IMHO, this is clearly a bug.

---

Now, to the solution. The "correct" approach would be to not use the ANSI version of the system call _at all_, but instead use the "wide" version. This is the approach MRI has taken, the bug was fixed there almost 3 years ago. :) ruby/ruby@9db6beb is the specific commit, fixing the bug reported in this issue: https://bugs.ruby-lang.org/issues/8508

I tried that first, by copying over their current version of the `Error` class. The only problem is that it depends on `win32/importer`, which we don't have, which in turn depends on `fiddle/import` which we don't seem to have either. You get the picture.

Therefore, I tried with a simpler workaround instead: _if_ we get an exception in this method, let's just retry by fetching the `en-US` error message instead. (inspired by how the code on the MRI side now looks: https://github.com/ruby/ruby/blob/trunk/ext/win32/lib/win32/registry.rb)
I have tested this with the customer; it works correctly as far as the code no longer crashes. _But_, it fails to retrieve the English error message (possibly because it's not available on that Windows installation). I am willing to live with that for now; if someone wants to fix that part as well, be my guest. The critical part for me and the customer is that the code must not crash on non-ASCII Windows installations.