I used Greg Swallow's script (
http://no.longer.valid/phpwiki/index.php/SME6.0.1Contribs-RemovalScript ), modified to remove addtional rpms to restore my SME server to the standard baseline in preparation for upgrading to V7.  Then I found that I cannot send any outgoing email, either with Outlook (settings unchanged since previous successfule use) or via Webmail.  
Outlook Send/Receive reports:
Task 'Nick's email on server - Sending' reported error (0x800CCC0F) : 'The connection to the server was interrupted.  If this problem continues, contact your server administrator or Internet service provider (ISP).'
Since I am the administrator that is a bit of a problem!
I then ran Yum Update to see if that would help - it didn't.  Any suggestions? I can post any logifiles suggested, but I am just not expert enough to work out what might be wrong.  Incidentally, the V7 update did not work - I think I have a CD hardware error, but I need to fix this problem first.