Hi David,
The file is probbly in a different format to quicktime, However Quicktime is the default player so it is telling you it is unable to play the file.
What we need to do is open quicktime and click on edit then preferences then go to Quick time preferences, Select File Types and set streaming by checking the box to SDP only set video to Quick time movie aand Digital video, Set Audio to whatever you want Mpeg set to 3gpp,3gpp2,amc,mpeg4, MP3 I leave unchecked and images i use Macpaint,Pict and quicktime.
Close your browser reboot and try that.
Hope this helps
Eric
IEEE Network Engineer, Microsoft
approx 20 years of experience from software to hardware design