Getting a bit fed up with this. The Downloader got to about 400MB and then said "Checksum error at chunk44."
Strange, from what I remember from the past week you're the first who is having troubles with Downloader. It can be your connection, especially if it's wi-fi. As a last resort I'd recommend downloading directly from browser. Links to all 7 part you'll find on the game page on GOG site.
Think you're right about it being to do with connection as I can close the downloader and re-open and it continues from where it left off.
The chunk reference must refer to the amount downloaded, as when it got to 2.38GB it gave the same error but at chunk238.
It's a connection with an ethernet cable, not wi-fi... and it's pretty fast so not sure what's the matter with it..