Question : Oracle, Oracle Applications Server, 10g Release 2 (10.1.2), installed on Suse Linux

Operating system: SUSE LINUX Enterprise Server 9 (x86_64)
No error messages. Process hangs. We kill the process, report sends the second e-mail (which is the third person on the list) then hangs again. ....

Answer : Oracle, Oracle Applications Server, 10g Release 2 (10.1.2), installed on Suse Linux

Thank you very much for those who tried to help me, but at last we found the reason. None of the above suggestions are valid in my case:
The answer is:
If you try to send the message with a "null" subject info, mail job hangs after the first person on the list. We filled up the "subject info" then everything worked fine. Just for your information.