In /wp-content/plugins/qtranslate/qtranslate_wphacks.php, line 89, change this:
// do some crazy js to alter the admin view
$content .="<script type=\"text/javascript\">\n// <![CDATA[\n";
$content .="function qtrans_editorInit1() {\n";
// include needed js functions
$content .= $q_config['js']['qtrans_is_array'];
$content .= $q_config['js']['qtrans_xsplit'];
$content .= $q_config['js']['qtrans_split'];
$content .= $q_config['js']['qtrans_integrate'];
$content .= $q_config['js']['qtrans_use'];
$content .= $q_config['js']['qtrans_switch'];
$content .= $q_config['js']['qtrans_assign'];
$content .= $q_config['js']['qtrans_save'];
$content .= $q_config['js']['qtrans_integrate_title'];
$content .= $q_config['js']['qtrans_get_active_language'];
$content .= $q_config['js']['qtrans_hook_on_tinyMCE'];
// insert language, visual and html buttons
Into this:
// do some crazy js to alter the admin view
$content .="<script type=\"text/javascript\">\n// <![CDATA[\n";
// include needed js functions
$content .= $q_config['js']['qtrans_is_array'];
$content .= $q_config['js']['qtrans_xsplit'];
$content .= $q_config['js']['qtrans_split'];
$content .= $q_config['js']['qtrans_integrate'];
$content .= $q_config['js']['qtrans_use'];
$content .= $q_config['js']['qtrans_assign'];
$content .= $q_config['js']['qtrans_save'];
$content .= $q_config['js']['qtrans_integrate_title'];
$content .= $q_config['js']['qtrans_get_active_language'];
$content .= $q_config['js']['qtrans_hook_on_tinyMCE'];
$content .="function qtrans_editorInit1() {\n";
$content .= $q_config['js']['qtrans_switch'];
// insert language, visual and html buttons
I basically just reorder some javascript code so that the qTranslate js functions are defined before they’re actually called. This stops them from generating errors when editing posts, which I believe was the source of the problem. This has fixed the deleted paragraphs issue for me. No other fix was needed.
I’m guessing the latest WP update did some internal changes to how javascript is displayed in WP admin, which messed up the order of qTranslate’s (hackish) way of inserting javascript so that some functions were called before they were defined.
Update:
Some additional fixes are available here:
http://www.qianqin.de/qtranslate/forum/viewtopic.php?f=3&t=2841&sid=3ba1e915e737302449d22837aaf853d2&start=180#p10352