Cubase Mac : Problem with OggVorbis Files via REAPER (Soft)

-Import a File OggVorbis Multitracks in REAPER (Software) and split it in single tracks.
-Save the single tracks in WAV or AIFF format, 16 or 24 or 32 bits (no importance).
-Import those Audio Files in Cubase.
-In Audio Editor, try to apply Gain, Normalize or any audio stuff on a file.

–> You get a awful noisy overloaded thing. It’s the same on Cubase 6(01) or 5.52…