Note that there is no rollback for SP2.
You also have to make sure that you have no post SP1 hotfixes installed. How do you make sure of this?
See the list of fixes in this KB article: http://support.microsoft.com/kb/953394/en-us
Or if you are having problems then you may need the CS2007SP1QFERemover tool:
http://support.microsoft.com/kb/954001/en-us
Unattended install of SP2 is possible but unsupported:
sp2setup /q /msioptions "QUIETINSTALL=1" /NoRestart /Log "%TEMP%\CS2007SP2.log"
And SP2 is English only.
