Major bug with the distribution of the V3 render.
This bug more than likely has been around since 1.26.4.23 release (although it has taken me this long to find it).
In Cool VL 1.26.4.26 on Windows XP, the Quicktime plugin (media_plugin_quicktime.dll) fails when attempting to play a video inworld.
There IS a workaround, however...
If you download the current version of the official viewer and install it, you can then go to the llPlugin directory (located at
C:\Program Files\SecondLifeViewer\llplugin) and copy the newer version of media_plugin_quicktime.dll to the Cool VL llPlugin directory (located at
C:\Program Files\CoolVLViewer-1.26.4\llplugin), videos will then successfully play in Cool VL
Attached is my Second Life Log file