@dasimser - you have two options. Either you can uninstall the existing buggy version using this from the command line:
calibre-customize -r "Search The Internet"
Then use the plugin updater (if you have it installed) to get 1.6.1
Alternatively, download the zip from the first post, and run this commandline:
calibre-customize -a "Search The Internet.zip"
Sorry for the inconvenience, thanks for reporting the issue.