Seems weird for a module to change the page title, when you could just put the page title you want in PageSettings.
However if you really want to change the page title from within the module don't modify the pagesettings object because by the time your module is loaded the pagesettings title have already been set on the page so changing the pagesettings object has no effect at that point.
Instead just change the title on the Page directly
Page.Title = module.Title;
however if more than one module on a page does this the last one wins.