Error message on sending

warning: array_merge() [function.array-merge]: Argument #2 is not an array in /home/drupal6/public_html/sites/all/modules/tellafriend/tellafriend.module on line 453.

The above appears whenever I use the "Tell a friend" module to send out an invitation.
If I add two email addresses as recipients, I get the error message twice.

The email does get sent and delivered, though, so nothing fatal is going on here.

All together, nice module - thanks for writing it.