Error Oment++ ogsEarth

Hi,

I was trying to install omnet++ but I get this error:

checking for osgEarth with CFLAGS=" -fPIC  -fno-omit-frame-pointer  " LIBS=" -Wl,--export-dynamic  -losgEarth -losgEarthUtil"... no
configure: error: Cannot find osgEarth 2.7 or later. Set WITH_OSGEARTH=no in configure.user to disable this feature or install an up to date version of osgEarth.

But I have ogsearth installed, what should I do? Thank you in advance.