Thank you 'Fortuny',
I have downloaded and paid for the software and used as instructed. But.
Now I have 'Mail" which is not able to run on my version of SnowLeopard ??
Software update says it is OK (up to date) and permissions are OK.
Confused. Apples help says re install 'Mail' - I don't know how (reason for original question).
Where to now???????
Before opening Mail, download the Combo Update for 10.6.7, and install it over the existing OS -- it will update the newly installed Mail app to be the version needed.
Btw, you could have inserted the install disk, chosen Optional Installs, and installed the Mail app without any need for Pacifist.