Some of the most common grammar errors are those of redundancy. In fact, there are so many such errors that I devoted an entire chapter (Play It Again, Sam) to them in Literally, the Best Language Book Ever.
Examples in the book include: and also, absolutely essential, completely surrounded, and PIN Number. A redundancy that’s common but didn’t make it into the book is referring to National Public Radio (NPR) as NPR Radio.
It should be obvious that the R in NPR stands for radio; therefore, saying NPR Radio is the same as saying National Public Radio Radio. We don’t refer to ABC (American Broadcasting Company) as the ABC Company or LBLBE (Literally, the Best Language Book Ever) as LBLBE Book–although, if you ask me, that’s catchy–so neither should we say NPR Radio.
–Paul
Paul’s book–Literally, the Best Language Book Ever
Everything Language and Grammar 