Having read the and followed the instructions provided on the wordpress website to upgraded my wordpress install, I noticed that the sidebar widget wasn’t working correctly, I couldn’t drag and drop the widgets. Here’s some instructions on how to fix that particular problem.
1) You should have a backup of your site , what you have to do is extract the the /wp-includes/js/scriptaculous/ directory and copy it to the wp-includes/js/scriptaculous/ of your wordpress installation using ftp. (If you don’t have a backup, then you can extract the directory from the installation website).
The directory /wp-includes/js/ of your wordpress installation should look similar to this.