Surprising translation dummy to: line

I discovered that if I send a message to "xyz group" (no quote marks,
with  
intended recipients in bcc: line) it gets interpreted as:

"xyz" <group>

before being sent and rejected as

"<Group@smtp108.prem.mail.ac4.yahoo.com>:
Unable to switch to /nonexistent: file does not exist. (#4.3.0)
I'm not going to try again; this message has been in the queue too long."

The bcc: list goes out just fine.

This is not a complaint, but a discovery that Opera mail (presumably) is  
trying too hard to correct what it thinks is a user error. Leaving the to:  
line blank works with no problems.

I have seen this kind of thing in a harmless way by Opera adding  
unnecessary parts to the from: lines. Part of this is some confusion about  
what information in the mail account setup is intended for the from: line.  
The instructions in "help" are not clear on this.

-- 
Leo H
Version 9.27 Build 8841
Platform Win32 Windows XP
Sun Java Runtime Environment version 1.6