I'm not really sure what your confusion is, could you elaborate? Also could you post a link to Immelts comments, I feel that there should be more to what he said that would clarify his position a little better.
I can break it down fairly simply based on the above quotes. Bershire hathaway does a lot of their business through investments and securities. They feel there are plenty of businesses that they can invest in inside the US and turn a profit.
GE does many different things. They have taken some of their profit from inside the US and used it to invest in their business (or acquire businesses) outside the US. If they were to bring this profit back to the US (repatriate) they would have to pay taxes on all of it. A substantial portion of GE is in manufacturing, and the company probably feels that there are other places that it would be cheaper to do manufacturing in, then in the US.
Edit: the above post is mostly IMO. It is tough to say what exactly the reason(s) is that GE doesn't want to repatriate the money.