JUser with ID: 42??

Hi world,

I have a problem with vm in this template. when I go to the "shop" in backend It shows me this error:
JUser: :_load: Unable to load user with ID: 42
I have never had an user with this ID number!! and if I make some changes in that page it doesn't save them.

Anyone can help me??

I solved enable the multivendor. I don't know if it is the right solution, but now I don't see any error.