Thank you very much Musichoo,
I am using an orchestral vst called Edirol Orchestral playing Erik Satie Gymnopedie 1. The vibrato that comes to the flute is not the normal vibrato of the patch, it is a heavy vibrato that moves the rate. I could not see any automation nor controller in the midi file, it is a GOST VIBRATO lol :) . I have turned off the vibrato depth and rate and the problem seems to be solved. The vibrato is affecting all the instruments of the orchestral. I read something on the web that satates that this midi file could be generating to a Garritan which uses a diferent controler for volume which is not the n 7 and may be affecting my vst.
If you want to find the GHOST Vibrato, I can send you the Erik Satie Gymnopedie midi file to check it out.
Thank you for your interest in trying to help me.
Best regards