This will work as long as the brace that closes the env block is the last one. To wit:

env {
   anything you want here
}
not-env {
   other stuff
}
[download]

is not going to work.

Now, it's possible that his input might look as simple as your example...but then he (hopefully) would have figured out a solution for that case already; something brain-dead like cat input | awk '{if (first == 1) {print l; l = $0;} else {first=1} }' for instance.

A poster above said it already -- if it nests, don't use regexes. Even if you do get it to work, you'll wish you hadn't.