Hi Josiane,
Can you please also post the log details from this file, like: sde_esri_sde.log? You can find the file from %sdehome%/etc folder, like: C:\Program Files\ArcGIS\ArcSDE\pgexe\etc.
One possible cause of this issue would be your ArcSDE repositories (database) are not matched with your ArcSDE binaries (software). For example, your ArcSDE binary files are in version 10 SP5, but your ArcSDE geodatabase still in version 10 SP1.
Thanks,
Ben L.