Add the relevant Ace3 libraries to your .pkgmeta (most likely you're not using the whole package, just some of the libraries it contains) and your TOC. This will tell the wowace packager to include the libraries with your addon, and load them for the user from within your addon's folder.
You should also add:
## OptionalDeps: Ace3
...to your TOC, so that users who don't want embedded libraries (eg. they prefer to download and install Ace3 separately and not have 75 copies of it in each addon they use) will still be able to load your addon.
AceGUI-3.0 actually doesn't use CallbackHandler-1.0, but it does require LibStub. Also, make sure you're using spaces instead of tabs (as Xinhuan mentioned) and don't forget the colon at the end of the "local" path:
You should also use no-lib-strip tags around the library references in your TOC, so they'll be commented out in disembedded packages. I'm not sure if it's still an issue (though I'd be surprised if Blizzard had done anything about it), but calling a nonexistent file from your TOC significantly increases WoW's loading time. (Doing the same from an XML file does not, though.)