Yes, I bought Locus Pro (actually Version 1.8.4) some days ago on Android Market and I have the same problems. Everything is fine when I'm online, but if I go offline I sooner or later get this this "This program is not legaly installed" notice.
It's a pity, it's such a great App and I bought it especially for using it offline....
It's a pity, it's such a great App and I bought it especially for using it offline....