If you didn't change your workflow since working cases, I suspect some software to have been installed or updated leading to a mismatch in codec usage in LivePano. Did you tried to reinstall Panotour Pro ?
If you are using Windows OS, please be aware that components capable of playing videos are often numerous and some may perform better than others. These components are part of DirectShow filters. Here is a list of tools that will identify and modify components used by default:http://codecguide.com/windows7_preferred
If you suspect your files to be incompatible with LivePano, please share them with us following these instructions: http://www.kolor.com/forum/viewtopic.php?f=3&t=766
. This will allow us to investigate deeper.