Several error messages or warnings appeared during the text-mode 
installs I did. On the mono monitor they appeared as a black streak
across the screen with no visible writing on them. I assumed it was
a colour the monitor was drawing the same colour as the background.
On the colour monitor, they appeared as a red streak across the
screen with no visible writing.

Flicking through virtual consoles did not show any likely-looking
candidates for these.

Some other errors messages -were- legible, but then large dialogue
boxes would be drawn on top of them before I could copy them down.
Can they always be saved to a virtual console somewhere as well 
as appearing briefly on the install screen?