Quick posting today – we had a customer seeing issues when printing from the Project Web App schedule web part where if they went over a certain number of rows (around 42 – spooky!) the printed page was blank (although the pop-up with just the grid displayed for printing looked just fine). This was after seeing this warning – which is expected – when you are printing a grid of more than 30 rows: Print Warning - There are more than 30 records in the current grid. Preparing the print page for this many records may cause the browser to alert that the page is running slowly.
In my testing internally I saw the same, I clicked OK on the warning, the new page opened with everything looking good and I could choose my printer – but the print was blank (I did try a large plan and in this case the final 40 or so tasks printed…)
However, if I turned off the compatibility setting under Tools, Compatibility View Settings, so that these were not applied to Intranet sites then all worked as expected and I got a good print. If you have explicitly set your PWA sites in compatibility you may see the same issue. If you really need prints though you may find Project Professional more flexible in giving you a good printed page.
*** Update 9/12/2011 I should point out this is based on IE 8/9 - it does appear that IE 7 has some issues with the PWA printing that changing settings cannot fix ***.