Just gave a try packaging Photoscape on XP that works well on XP and Win 7. I can share the ThinApp project folders if you want.
I'm not much aware about virtualbox but make sure you capture on a clean vanilla OS with latest version of ThinApp (4.7.3) installed.
For troubleshooting, please have a look here:
Application Troubleshooting Tools and Tips for VMware ThinApp | VMware ThinApp Blog - VMware Blogs