I tried both Pali's isntructions, and later, upgraded to latest CSSU as per merlin's.

BTW, I'll answer myself - yes, chmod +rwx gives proper permissions to ke-recv. In fact, this step isn't needed when fixing manually - after dpkg-deb ke-recv_3.19-15_armel.deb, ke-recv have good permissions, so moving/copy'ing it is enough. Unless someone unpacked it to VFAT...

Still, I don't know WTF - why it's affecting some people only?