[support] WorldPay callback Errors

I have ecommerce with WorldPay integration, and the back end is working, BUT when WorldPay displays the callback page, with URL like: https://select.worldpay.com/wcc/card?op-PMGetNextPage&PaymentID=mg1imsps........ etc. I see: warning: array_keys() [function.array-keys]: The first argument should be an array in /var/www/vhosts/mysite.org/httpdocs/modules/user/user.module on line 378. warning: array_fill() [function.array-fill]: Number of elements must be positive in /var/www/vhosts/mysite.org/httpdocs/modules/user/user.module on line 379. etc--like 10 such lines. anyone have any idea what that could be? Thanks