when yu say you removed it...how?
Either by the uninstaller, deleting the files that are usually in c:\program files, deleting the battlefield 2 folder that's in my documents or deleting the registry entries (or a combination of the above)
If you've just manually removed some files some stuff like the registry key will still be there. An installation of the game might think that things are still installed and try to patch them
To start from scratch:
Delete (or better RENAME) the battlefield 2 folder in my documents
remove the c:\program files\ea games\battlefield 2 folder (this from memory so may not be exact)
try running the installer again