I came across this error the other day. I’ve installed SQL 2008 through 2012 without any real issues. Recently, I was trying to run the installer again so that I can add some features. I kept getting this message. It would even come up when I would try to do a change from Add/Remote Programs. I figured out the fix and it was pretty simple.
C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\SQLServer2008R2\Resources\1033
Make sure you overwrite the file.