Roundcube Error Sending Mail

I got Roundcube installed OK by following the Wiki. I set up all the user accounts and they log in OK. When I try to send a message from any account, I receive a “Failed to Send Message” error. Also, the sender line is blank by default.
The error that shows in the log is:
"[12-Jul-2006 15:30:31 -0700] SMTP Error: SMTP error: No From address has been provided
in /home/xxxx/xxxx/ on line 230"
I have tried both having the SMTP username and password be %p & %u, and using a specific user m1234567 and password. Both produce the same error.