Ok I'll give a refresher about plugins. On the mac the plugins are  
dumped either in the same
folder as the VM, or if the VM is an os-9 package, then the same folder  
as the package.

OR a little known fact:
They can be dumped in a folder called Plugins

Technically the
MySqueak Folder
	Squeak 3.4.0b2.app		/* an os-9  package */
	Plugins		
		mpeg3Plugin		   /* that's the os-9 or lower one */
		mpeg3Plugin.bundle   /* that's the os-x one */

Now an os-9 package appears to be a regular application folder and  
everything is ok. The operating system launcher picks
the right binary based on the hosting os (os-x or os-9). However for  
pre os-9 users it's a bit confusing, the "Squeak 3.4.0b2.app"
appears as a folder, which contains this

Squeak 3.4.0b2.app  (the package which really is a folder) contains:
	Squeak 3.4.0b2 Classic  (an alias to the os-9 application to make the  
os-9 finder happy)
	Contents
		pbdevelopment.plist			/* some xml files for the os-x bundle*/
		Info.plist					/* some xml files for the os-x bundle*/
		MacOS
			Squeak VM Opt.sig		/* a gnupgp signature for the binary */
			Squeak VM Opt		/* the binary for the mac os-x  VM */
		MacOSClassic
			Squeak 3.4.0b2 Classic.sig /* a gnupgp signature for the binary */
			Squeak 3.4.0b2 Classic	/* the binary for the Mac classic (os-9) VM */
		PkgInfo					/* package signature to make os-x finder happy */
		Resources
			SqueakScript.icns		/*  icon files for os-x */
			Squeak.icns			/*  icon files for os-x */
			SqueakPlugin.icns		/*  icon files for os-x */
			Squeak VM Opt.rsrc		/*  resource fork for os-x */
			SqueakImage.icns		/*  icon files for os-x */
			SqueakChanges.icns /*  icon files for os-x */

> Squeak 3.2.7Beta6.app

I would suggest you upgrade to 3.4.0b2

In your  note you discuss
> (1) "Squeak 3.2 VM" (an alias)

what does that point to?

> folder (2) "Squeak 3.2.7Beta6.app "

That's the package

> So what I needed was
>     {WhatLooksLikeTheVMfolder}:Squeak  
> 3.2.7Beta6.app:Contents:MacOSClassic:

I believe it works this way because you are using 3.2.7b6. About that  
time we changed where it looks because that
was confusing to people, and required digging into the package. So with  
3.2.8   or higher (or later versions of 3.2.7) the plugin should be  
position
as mentioned in the start of the note, beside the *.app or in a plugins  
folder beside the *.app If this is not the case with say 3.4.0b2 please  
let me know.

> Now that I've got the plugin in the right place, it plays the file,
> BUT it's a bit jerky.  (About four painful breaks in about 15 seconds.)
> (266 MHz PowerPC G3, with an audio card, whatever that is.)

Try increase the memory used by the VM, to do this if you are running  
os-9  you can do a get info on the Squeak 3.4.0b2.app
For earlier than os-9 you need to dig down to the VM in the  
MacOSClassic folder. I think it is set to 30MB, try 40MB.

--
======================================================================== 
===
John M. McIntosh <johnmci at smalltalkconsulting.com> 1-800-477-2659
Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
======================================================================== 
===