In case your dotProject application is displaying incorrect days of the week, you can easily resolve the issue by editing the following file:

dotProject_directory/lib/PEAR/Date/Calc.php

Find the line:

$output .= Date_Calc::getWeekdayAbbrname($day,$month,$year);

and replace it with:

$output .= Date_Calc::getWeekdayAbbrname($day,$month,$year + 8);