This error is strange - that particular portion of the install file hasn't changed since 2.2.0, and hasn't been encountered before. I've uploaded a new 2.2.1 install file that should avoid this error. Sorry about this - hopefully this one works properly for you!
Jason Rhinelander
Gossamer Threads
jason@gossamer-threads.com
Jason Rhinelander
Gossamer Threads
jason@gossamer-threads.com