From what it seems some of the application files are corrupted or in conflict with other similar files from the first installation. In order to fix the issue, I suggest you completely remove the program (Control Panel > Uninstall a program) and run a registry cleaner like CCleaner or Glary Utilities. After that, reboot your computer, connect your TeXet MP3 Walkman to your PC and install the program again. This should fix it.