remove unnecessary semi-colons (keep compiler warnings quiet).
Cast to NSMutableArray to avoid a compiler warning about ambiguous -addObject:. This is not likely to be something normally encountered, as the other -addObject: is coming out of the Nimbus 3rd party library.
add autorelease to avoid possible memory leak.

The various "parse xxx" methods do return auto-released objects, and so the string object ought to do the same.