Adobe Photoshop Express Uploader was a desktop application based on AIR technology. It was used to upload and sync photos from your desktop to Photoshop.com. From what it seems, it has been discontinued and replaced by Photoshop Express Editor, which is an online tool that doesn't need any authentication information in order to use it. However, if you want to change the Adobe account information, you need to follow the instructions provided by the Support team.