Hi,
HikaAuction has no language file for Spanish so far.
And if I check the file where the error happens, it says that the issue is with the text for the translation key AUCTION_FINISHED_WINNER_EMAIL_MESSAGE which is a translation key of HikaAuction.
So what that means is that you probably made a translation override for AUCTION_FINISHED_WINNER_EMAIL_MESSAGE for the Spanish language in order to translate the text but you made a mistake in it regarding the %s
Here is the English one:
AUCTION_FINISHED_WINNER_EMAIL_MESSAGE="The auction of the product '<a href=\"%s\" >%s</a>' in which you have participated is finished. Congratulations, you won the auction for %s."
As you can see, there are exactly three %s. Yours for the Spanish must have either too much or not enough %s.
Since you didn't provide the error message, only the call stack, I can't say which one for sure.