Problem: The SMS client isn't being sent out to our new/re-setup machines and I don't know why!
I eventually got round to having a look at
C:\WINNT\System32\ccmsetup\ccmsetup.log
on the client machines SMS was trying to install on. Every 10 minutes SMS was trying to install the client on the machine, this failed everytime with the same error message.
Googling produced this result which lead me to have a look at the accounts SMS was using to install the client with.
I first found and altered Systems Management Server -> Site Database -> Site Hierarchy -> -> Site Settings -> Connection Accounts -> Client , with no luck.
I then found and altered ... -> Client Installation Methods -> Client Push Installation -> Properties -> Accounts , again with no luck
Finally, after looking through the SMS help guide I found and altered ... -> Component Configuration -> Software Distribution which stores two account and password settings (one for the different types of clients).
Lo and behold it worked. The SMS client started being installed on the machines!