What Practical Problems Does Dina Zielinski Describe in Storing Data in DNA?

On TED Talks Daily, Dina Zielinski says DNA outlasts man-made devices, but it is not perfect. You recover a stored message by sequencing the DNA, and every retrieval uses up some of that DNA, because loss is part of sequencing. Sequencing also writes errors into the A's, T's, C's, and G's. Copying the DNA is cheaper than synthesizing it again. Her team made about 200 trillion copies of their files and got the data back. To live with the errors, they borrowed an algorithm used for streaming video, which also has to rebuild an original file from enough zeros and ones.