i am not 'from Auctiva' but i'm pretty sure that this error is related to the problem that E-BAY has been having that they have yet to fix (and aren't sure when it will be fixed)
from what i understand it has nothing to do with Auctiva. it is happening with all third party launching services.
i had one listing with this error yesterday and i checked E-BAY and the listing had actually posted so i would be careful and check on E-BAY before rescheduling or relaunching.