The library is not able to correctly separate header and body in some cases. I am attaching a sample message.

It could be that the expression used to find the separation is greedy. I have verified that the following regular expressions
works correctly:

    /^(.+?)\r?\n[\s\t]*\r?\n/m

Date: 2008-12-01 04:58
Sender: Matt Armstrong

Hi, I'm afraid I don't know what regexp your are talking about
above.  Can you provide more details?  I notice you have \r?
in your regexp -- the library doesn't deal well with \r\n sequences
in input.  It is better to do \r\n -> \n conversions before
giving a message string (or file) to a RubyMail parser.