QuickTime
AAC VBR Bug NOT a Bug
According to this article at MacFixIt, "it now appears that this [is} neither a bug in QuickTime nor a bug in iTunes; in fact, it's not a bug. What's happened is that the meaning of the choices you make in iTunes has changed (without, as usual, any explanation or notice from Apple)." For more, read the entire article.
QuickTime 7.3 Bug - AAC VBR, Whether You Want It Or Not
This thread and this thread at Apple Support Discussions describes a bug in QuickTime 7.3 which ignores your iTunes VBR (variable bit rate) settings for importing or converting AAC tracks. As a result, you always get VBR. (Thanks to Correspondent Christian who pointed this out to me when describing a problem with the "Pass-Through" setting of Join Together. This option will only be available if your selected tracks all have the same bit and sample rate. Of course, if they are VBR, they won't all have the same bit rate and Pass-Through won't be available.)
I smell iTunes 7.5.1 and/or QuickTime 7.3.1 coming soon. At least, I hope that's what I smell.
iTunes 7.3.1 and QuickTime 7.2 Released
Yesterday Apple released iTunes 7.3.1 and QuickTime 7.2. "iTunes 7.3.1 addresses a minor problem with iTunes 7.3 accessing the iTunes Library." This is the -50 error some people were getting when trying to update the library. I have not noticed any AppleScript-related changes. QuickTime 7.2 finally allows non-Pro users to view movies in full-screen plus contains additional bug and security fixes. It also provides an updated H.264 codec for exporting movies to an iPhone-compatible format.
Also, several Intel Mac users are reporting that applications fail to start and that Rosetta seems crippled after installing the latest QuickTime and/or iTunes. Ouch.
UPDATED: Join Together v5.1.2
Join Together has been updated to v5.1.2. A couple of months ago I started getting reports from Join Together users regarding a strange "-54 file open" error. This error occurred as Join Together was attempting to apply tags to the joined file in iTunes. Turns out that iTunes 7.1.x is busy analyzing audio data during the "add" routine, thus leaving the file open and preventing the tags from being applied. I couldn't duplicate the error myself (still don't know why), so I had to rely on the kindness and patience of a good dozen or so users to fix the problem. Looks like it's licked. Also, the "-2753 variable" error that some people were getting has also been fixed. This was another error that I was unable to duplicate, so, once again, many thanks to the beta testers for their patient assistance.