Browsing Dutch translation

That's meant to be the name of an item (%0) and the percent done (%1).

The stdio UI uses this to show current status (%0),
and overall progress as percentage of work complete (%1).

This prompt is shown to the end-user after an End User License Agreement
has been displayed, asking them if the license text is acceptable to
them. It's a yes/no question.

This is a GTK+ button label for yes/no/always/never questions.
The '_' comes before the hotkey character.

This is an error message reported when a .zip file (or whatever) that
we need can't be located.

This prompt is shown to the user when they click the "Cancel" button,
to confirm they really want to stop. It's a yes/no question.

The opposite of "next", used as a UI button label.

This is a GTK+ button label. The '_' comes before the hotkey character.
"Back" might be using 'B' in English. This button brings up a file
dialog where the end-user can navigate to and select files.

All the "BUG:" strings are generally meant to be seen by developers,
not end users. They represent programming errors and configuration
file problems.
This is shown if the configuration file has specified two cd-roms (or
whatever) with the same media id, which is a bug the developer must
fix before shipping her installer.
"media id" refers to Setup.Media.id in the config file. It's not meant
to be a proper name, in this case.

This is shown if the configuration file has no installable options,
either because none are listed or they've all become disabled, which
is a bug the developer must fix before shipping her installer.