You're right jimlad, the link version is 2.0.0.25 but on my latest OS for the 9700, the version is already 5.0.0.35 and it solved the sync problem from 2.0.0.25
Using the link i installed .25, i "had" .35, but it was not there.
Its not here now either
Posted from my CrackBerry at wapforums.crackberry.com
I had the exact same problem. To fix it I had to edit the net_rim_bb_gmail.alx file so the </required> and </hidden> fields were both false. Then I could reload version .25 through the blackberry desktop.
I tried installing and removing the plugin and removing and replacing the BIS account and services books probably 20 times over a few days and never could get the plugin back.
The file is located in Program Files/Common Files/Research In Motion/Shared/LoaderFiles/[your BB OS]/