After it feel I like Hulk !!
This come, I think, from the fact that for Authors columns, designers have used a fixed width of 150 pixels, and that the second column has a size expressed in percents.
Maybe (more than probably, I already had a lot of probs with designing CSS stylesheets for IE) is the print engine in IE quite bad for portrait layout. Landscape printing does not cause any problem, of course... but is not ease of use to review printings...
May I suggest the site admins (I know : you have already a lot of work... Especially with boyz like me :-)) to try to locate the place where author headers and contents are displayed and to try a percentage value in place of fixed value.
On a second hand, I personaly use the technique of CSS media selection, making that a div or named section with a css setting 'display:none' only on printed media will not be displayed. So, the all place is available for the printing of the pertinent information... making visitors happy not to choose a specific 'printer version'...
Maybe should I direct someone from the phpBB development team to this topic ?