  The orbital distributions of currently observed extrasolar giant planets
allow marginally stable orbits for hypothetical, terrestrial planets. In this
paper, we propose that many of these systems may not have additional planets on
these "stable" orbits, since past dynamical instability among giant planets
could have removed them. We numerically investigate the effects of early
evolution of multiple giant planets on the orbital stability of the inner,
sub-Neptune-like planets which are modeled as test particles, and determine
their dynamically unstable region. Previous studies have shown that the
majority of such test particles are ejected out of the system as a result of
close encounters with giant planets. Here, we show that secular perturbations
from giant planets can remove test particles at least down to 10 times smaller
than their minimum pericenter distance. Our results indicate that, unless the
dynamical instability among giant planets is either absent or quiet like
planet-planet collisions, most test particles down to ~0.1 AU within the orbits
of giant planets at a few AU may be gone. In fact, out of ~30 % of survived
test particles, about three quarters belong to the planet-planet collision
cases. We find a good agreement between our numerical results and the secular
theory, and present a semi-analytical formula which estimates the dynamically
unstable region of the test particles just from the evolution of giant planets.
Finally, our numerical results agree well with the observations, and also
predict the existence of hot rocky planets in eccentric giant planet systems.
