I might have found my problem.

I use winmerge to compare all file related to paypal ipn on server and in default archive of zencart 138a

All files on my server had a different end of line return. not sure which file had the unix and who got the windows.

I uploaded all files from archive related to ipn to server and voila it work.

I tried something else, I remove the ipn from admin, reinstalled it, and again, not working. Files had the same different end of line char.