I am trying to fix
http://forum.virtuemart.net/index.php?topic=109425.0 to no avail and no one is helping me, but so far I think i've come across how to solve your problem after trying to fix my issue :S
So here's what i think you need to do,
You can either try going to your shoppers in virtuemart and selecting everyone and choosing NOT A VENDOR. And then you can choose Is a vendor for only the account in which you want to be the vendor account. Usually this account shows up under 'shop' and copies over the information and the e-mail or you can change the e-mail directly under 'shop.' If this works correctly but it might not work in the database, i think this may be a jUpgrade issue which I also came across because I had this issue on a migrated website.
Be sure to double check in phpmyadmin for j25_virtuemart_vmusers and browse in that for any users that have user_is_vendor set to 1, disable them and give them no vendor Id either, set that to "0". Now change the one account you do want to be the vendor or to have the e-mail address used for registrations/invoices (your shop) and set the vendor id to 1 and the user_is_vendor to 1 for that account by searching via it's virtuemart user id.
This should deffinately alter the information under 'shop' thereafter.
This should solve your problem but not my problem where I want a seperate e-mail address only for user registration confirmation e-mails or to disable that feature