I just noticed this error: Page Not Found Smarty error: [in evaluated template line 46]: syntax error: unrecognized tag 'mtactionstreams' (Smarty_Compiler.class.php, line 580)
This is showing up in my sidebar on my entry pages, which are published dynamically.
For example: http://www.rhinoblues.com/thoughts/2008/08/combining-entries-with-action.php
Reported on Movable Type 4.2

The Action Streams plugin doesn't support dynamic publishing.
Ahh...I must have just spaced it earlier.
I just used an argument to switch widget sets for dynamic published pages.
Sorry an [mt:ifdynamic] argument.
Sorry an [mt:ifdynamic] argument.
For anybody in the future, you can still take advantage of dynamic publishing and an Action Stream. Instead of dynamically including your Action Stream module, publish your Action Stream to a file (don't dynamically publish it, duh), then dynamically include that file's contents into your pages.
<$mt:include file="/path/to/action_stream.inc"$>
It works like a charm and accomplishes the same thing. (I mainly wanted to use this so I could still include my Action Stream on my dynamic error page.)