I recently downloaded the game 1.0.8b (24344).
When i run the installer it says

"The source file is corrupted
You should run the installer's integrity check to verify which files need to be re-downloaded."

I tried to rename the file as well. It asked me to locate part 6 of the .bin files.
When selecting the correct folder, it says that it cannot find the file (i didn't rename part 6).
It found the file when .exe and .bin file have the same name, however it just reverted to the case of "The soure file is corrupted"

I ran into this same problem a few days ago. It turned out that when I downloaded the 1.0.8b game files three of them (1.bin, 2.bin and 6.bin) were only 1.5Gb in size instead of the listed 4 Gb (3.6 Gb for 6.bin). I notified Support about this and they never got back to me, however, I re-downloaded these files yesterday and the problem with file size was apparently fixed. This has happened to other people to.
I also re-downloaded the installer and it proceeded to install. I used the file integrity check during install and it told me that the other three files (3.bin, 4,bin and 5.bin) were corrupted. After I downloaded these the game installed.
I think that if you check the downloaded file size of 1, 2 and 6 .bin and they are not 4 Gb then you may have the same problem.

We don't tolerate piracy here :/

Get a job, thief.

I am just stating that the file sizes are correct in other sources, not that i got it from there.
If perchance those file composition are incorrect, just do say so. I won't bother asking here if i can simply redownload working copy from pirated sites

A thief is a thief is a thief.

"however, after extraction the file composition seem to be similar"

"I am just stating that the file sizes are correct in other sources, not that I got it from there"

Mission failed...