Google Earth (at least version 5.0.11733.9347) depends on glib and libXrandr; those dependencies should be added to the ebuild. In particular, it looks for the libraries "libgthread-2.0.so.0" and "libXrandr.so.2", which are in those two packages. (Most people have those two packages installed already, which is presumably why they were missed as dependencies. I discovered the need for them when installing Google Earth in a fresh 32-bit chroot, on an otherwise AMD64 machine -- necessary because the emul-linux-x86 stuff is too woefully out-of-date to run Google Earth on my machine, which has Intel graphics.)
Fixed, thanks for reporting.