  The isoscalar giant monopole resonance (GMR) in spherical nuclei
$^{100-132}$Sn, $^{144}$Sm, and $^{208}$Pb is investigated within the Skyrme
random-phase-approximation (RPA) for a variety of Skyrme forces and different
pairing options. The calculated GMR strength functions are directly compared to
the available experimental distributions. It is shown that, in accordance to
results of other groups, description of GMR in Sn and heavier Sm/Pb nuclei
needs different values of the nuclear incompressibilty, $K \approx$ 200 or 230
MeV, respectively. Thus none from the used Skyrme forces is able to describe
GMR in these nuclei simultaneously. The GMR peak energy in open-shell
$^{120}$Sn is found to depend on the isoscalar effective mass, which might be
partly used for a solution of the above problem. Some important aspects of the
problem (discrepancies of available experimental data, proper treatment of the
volume and surface compression in finite nuclei, etc) are briefly discussed.
