Why can't I link2sd the Play Store and Maps apps?
The author of an app can set a flag in its manifest (the package description) to say whether it can be moved to external storage or not. If you try to install a package to external storage, and its manifest says it cannot be installed there, you get the error code you describe.

Google's developer documentation provides a list of kinds of apps which should set the flag to prevent themselves being installed to external storage, because of undesirable side-effects if the external storage is removed.