Just FYI - I don't have a PRO-668 but I think most things are the same on the PSR800 and WS1080...
Some things to try....
Skip to auto-update option. Try using the "Updates" menu.... select "Check for Library Update". This really should be the same thing but ... just in case.
Next option --
On my machine, I have a folder called EZ Scan Digital (for my PSR800).
Since your radio is a PRO-668, I suspect this will be similar for you but not the same.
On your PC and in your home directory, do you have a folder/directory called something like iScan, etc. that contains the library (sub folder folder names like DB and/or LDB)?
If so, can you rename them (ex: DB -> DB371, LDB -> LDB371, etc.) and then try downloading the update again? Just curious.
Seems like others are downloading updates (or have in the past). Does anyone know if there are any server problems (i.e. others are not able to do the update either) or is that working for others? Need to rule out a problem that is affecting everyone (but that doesn't sound like it is the case).