downloaded game asks for disk 1~

[Zanderat]

We just downloaded the online windows version of the game, it downloaded fine, but upon unzipping and installing, it came to a set up screen that said:

Please insert disc 1 and click ok
there was a browse box and the location of the downloaded file already filled in the box... but when I click ok it says

the file "amnisia_tdd_1.0.1... can not be found...

whats up, its a download, we didnt get a disc

Where did you *buy* it from?