The script does not look like its a Plug-in Script so you cans not record setting for it in your action. The only option you have is to make that step interactive. Check the box in front of the step to turn one the scripts dialog. If you good at scripting you could write a script like that one the is a Photoshop Plug-in. Then the folder you used recording the step will be passed to the plug-in when the action is played.

I copied the default action and modified it's code.
in my case this was the script:
"Layer Comps To Files.jsx"
I modified
...
exportInfo.destination = Folder(app.activeDocument.fullName.parent).fsName; // destination folder
to my folder, e.g:
exportInfo.destination = File("/C/Documents and Settings/" + $.getenv("USERNAME") + "").fsName;