I believe that the InstMsiA.Exe & InstMsiW.Exe files are unneeded - I think they are for updating the windows installer. With XP - they should be up to date already.
Not 100% sure - but it might be something you can check out.
this would save you some space on the cd.
Did a quick google -
CODE
To download the Windows Installer file from the Web, visit one of the
following Microsoft Web sites:
Instmsia.exe for Windows 98 or Windows Millennium Edition:
http://download.microsoft.com/download/WindowsInstaller/Install/2.0/W9XMe/EN-US/InstMsiA.exe
-or-
Instmsiw.exe for Windows NT, Windows 2000 or Windows XP:
http://download.microsoft.com/download/WindowsInstaller/Install/2.0/NT45/EN-US/InstMsiW.exe