An easy fix that has worked for me…
The quicktime plugin was disabled in the Internet Plugin dir.
Try the following:
got to “/Library/Internet Plug-Ins/Disabled Plug-Ins” and check if “QuickTime Plugin.plugin” is there, if so, move it to “/Library/Internet Plug-Ins/ , restart Safari and try that webpage that had quicktime.
For me it was my online voicemail call log (PBX Phone System) at the office.