SQL & PL/SQL

utl_mail.send malforms messages

Hi,
I am trying to send simple text emails using utl_mail.send. If I receive the message to my thunderbird or outlook clients, I can read the body of the message. If I send the email to my cellphone or read the email in my browser-based webmail, the body of the email is lost. I have been using UTL_SMTP successfully for years, and don't have these problems. I want to use UTL_MAIl so I can send simple attachments, but I can't get the thing to go even for simple stuff!
Here is my code:
BEGIN
utl_mail.send (sender => 'steve.west@more4apps.com',
recipients => 'steve.west@more4apps.com',
subject => 'My Subject',
message => 'This is my body');
END;

Thanks,

Steve

PS My db version is 10.1.0.4.0