The problem appears to be that the customised version of jquery-mobile breaks when it loads after the standard WordPress installation of jQuery.
I think you’ve got two options:
One is to keep going with Diapo – but install it with code along the lines of:
<?php
wp_enqueue_script( 'jquery-mobile-customised', get_template_directory_uri() . '/js/jquery.mobile-1.0rc2.customized.min.js', array('jquery') );
wp_enqueue_script( 'jquery-easing', get_template_directory_uri() . 'js/jquery.easing.1.3.js', array('jquery','jquery-mobile-customised') );
wp_enqueue_script( 'jquery-hoverintent', get_template_directory_uri() . '/js/jquery.hoverIntent.minified.js', array('jquery','jquery-mobile-customised','jquery-easing') );
wp_enqueue_script( 'diapo', get_template_directory_uri() . 'js/diapo.js', array('jquery','jquery-mobile-customised','jquery-easing','jquery-hoverintent' ) );
wp_enqueue_script( 'diapo', get_template_directory_uri() . 'js/yourscript.js', array('diapo' ) );
?>
I think you may need to modify jQuery mobile to work with WordPress.
Another much simpler option might be to use Rotating Tweets’ installed version of jQuery Cycle 2. Pick version 2 of the script on the settings page and replace:
<div class="pix_diapo diapostarted">
with
<div class="rotatingtweets">
All the options for jQuery Cycle 2 are here.