Getting this error message!
SMTP servererror: 5.7.1 Service unavailable; Client host [78.46.81.70] blocked using xbl.spamhaus.org; http://www.spamhaus.org/query/bl?ip=78.46.81.70
That is nothing to do with VirtueMart. The message is that you were trying to send mail though a Spamhaus blocked IP address. I just checked that IP address and it is not blocked now.