ok both are fixed for now

the 500 error just vanished without doing nothing, and your idea was right, i did check the ids and indeed there was a mismatch, one user did not existed so i had to instert all the users again to make it work right, and after that i had to change the user_is_vendor to 1 only for the specific user i wanted to be a vendor.
All fixed for now.
Thank you GJC Web Design
P.S.
Also i have to say that this error "ERROR vmError: $link["view"] is empty" is for sure a virtuemart menu link problem that has to be relinked or unpublished to stop.