[Zope] error with simple python script loop

[Christian Steinhauer]

>>I just cut and pasted your code into a python script on my 
>>Zope installation 
>>(2.9.2) and it worked as expected (ie. 2 emails sent). So 
>>something is 
>>pooched in your installation.
>>
>>A quick way to check to see if your script is looping more 
>>than you expect 
>>is to do something like:
>>
>>loopCheck = []
>>for i in range(2):
>>  subj = str(i) + ' range python'
>>  context.MailHost.send('range test with python', "rec at mail.com", 
>>"sender at mail.com", subj)
>>  loopCheck.append(subj)
>>return loopCheck
>>
>>If you are getting only 2 iterations of the loop (as it 
>>should be), then 
>>something is wrong with your MailHost (if this is the case 
>>try deleting it 
>>and re-adding it).  Another test: place a local copy of 
>>MailHost in the same 
>>folder as your script and see what happens.

Hi Jonathan, thanks for taking care of the problem. I have done the self test you do with the list. But everytime when something is written at last line, example return 'eof' (My example in the topic) the error did not occured - so the list gives me 2 and i will get 2 emails.

The error only occured when nothing is written under the loop. 

I have 2 real separeted dedicated servers, one with zope 2.6.4 and one with 2.10 - the problem occured on both servers.
So i used the zope product "MailDropHost" too and get the self error on both server. With MailDropHost i can see a spooler - thats nice - but in the spooler i see 4 emails. So the Operating System or Exim get 4 Mails from Zope/Python. 
I´m using Debian Linux.