can you do a spotlight search for Cookie, then move it to the trash, and reinstall from Mac App Store.
also try this:
How to Force the Mac App Store to Let You Re-Download an App
If you hold down the option key and click the Purchased icon at the top of the App Store window, there's a good chance that the status button for the app in question will change from "Downloaded" to "Download," or from "Installed" to "Install." It's not a sure thing because Apple seems to leave it up to the app developer to decide whether or not to support optional downloads.
Another method that sometimes works is to option-click the "Installed" or "Downloaded" button. When this works, the download process will start right up."
found the stuff, eventually got it all deleted.
When I try to re-install it now, though the app store keeps saying that the app 'failed to download' and I get stuck again.
SO I have no cookie at all at this point. Can I manually download and apply it that way?
I installed 'Safari Cookies 1.9.8' (downloaded from your download page).
The 'Safari Cookies.bundle' is present in the SIMBL Plugins folder and the 'Safari Cookies' UNIX executable is present in the bundle.
But where is the user interface? How is it used?
There is no Safari Cookies app in the Applications folder. There is no Safari Cookies Preference Pane in System Preferences. I can find no mention of Safari Cookies in Safari Preferences or in any of Safari's menus.
OS X 10.6.8, Safari 5.1.9, 12 Gig of ram, 41 Safari windows open with 6 tabs across two monitors
A ReadMe file might be helpful, or even some screenshots on the download page.
for Safari Cookies,
try reinstalling, and do a custom install,
make sure SIMBL is checked.
load up a url (important)
then open Safari's preferences.
you will see a cookie icon, that is Safari Cookies preferences.
(you may need to click the 2 small arrows at the right of the preferences window to see it)