FIXED - eDocman Indexer won't install

I've just purchased and installed the latest eDocman on a localhost test site running Joomla 2.5.9 and now I want to install the PDF indexer plugin.

I downloaded it from here - is the the latest version?

When I tried to install it I get the message "There was an error uploading this file to the server".

Any ideas what the problem might be please?

Mike

EDIT: I found that by unzipping the plugin file I can install it from a directory. Slightly confusing ..