The host PC lacks the correct codec (e.g., missing MPEG-2 or old AVI codecs). Solution: Convert videos to WMV format (which Windows XP/2003 handles natively) or install the K-Lite Codec Pack (requires admin rights, defeating portability).
Microsoft PowerPoint 2003 was never officially released by Microsoft as a "portable" application. However, there are official and unofficial methods to use its functionality without a full local installation. Official Portable Solutions PowerPoint Viewer 2003 portable : Microsoft provided a standalone PowerPoint Viewer Microsoft PowerPoint 2003 - Portable Version
