I get this message whenever I try to set one of my panels to a front orthographic view:
Warning: Could not find an appropriate startup camera: front. A substitute will be used.
But I can set the panel to 'front', it just doesn't do it automatically upon startup as it normally would in the 4-panel persp/top/front/side setup (counter-clockwise from topright).
Readjusting it manually wouldn't be a problem, except for the fact that it sets the two bottom panels (in the four panel view) to the same view and whenever I change one, it changes the other.
"a foolish consistency is the hobgoblin of little minds." - rwe