Looks like Ubuntu does a mess with its fpc package. The real compiler is ppc[ross]XXX where XXX being the target architecture and ross infix being an indicator of a cross compiler, fpc itself is just a "driver" that selects the correct ppc[ross]XXX based on -P parameter (defaults to architecture where fpc itself is compiled for). It should be a symlink in the /usr/bin to the same ppc[ross]XXX binary in fpc directory, which normally installs as /usr/lib/fpc/$fpcversion. Please check that. Check also your fpc.cfg to ensure the paths are valid.