Hi Mike,
May be you already did it, may be not, ... if you didn't , why not try to trash all files which are present on your HD for which the file name contains QuickTime or QTime,
Especially make a search in the main Library, in the Library located inside the OSX System folder, in the System folder itself, so everywhere each time you find a file related to QuickTime you trash it , any kind of file which is related to the applications, preferences files, Applications, Plug-Ins, documents, support documents, extensions and so on, packages...
=> all in the trash .
Repair Permissions,
And then try to install QT 6.5.2 ... (or QT 7.01 and then the 6.5.2 re-installer)
Francis