The (auto) function of distribute has been removed from Illustrator; yet it remains in Indesign CS4 and there seems to be no way to set a reference object in Flash. I wish they would be consistent across CS4, if the idea is to increase producivity and reduce the learning curve.
You have to explain this better or it seems to me that you are missing the options available to you in AI like align to selection, align to artboard and align to key object.
If you use align to key object you have a specified distance available other wise it is automatic as far as I can tell.
Here is a screen shot of the Align Tool for Illustrator, InDesign and Flash, there is no consistency in use or function.
It used to be I could select a collection of objects and distribute them between the end objects simply by selecting (e.g. the red and magenta objects) and the others would be spaced equidistant between.
For alignment Flash does not seem to even have a way to set the reference object.
I am still with 10, so I could not say what it should look like in CS4, but missing options may be caused by preference corruption. If that is the case, you may try to Ctrl+Alt+Shift/Cma+Option+Shift during startup or to Move the folder with Illy closed.