I'm not sure why this is happening on your particular machine...[/url]
I know why Rob... It's really not as common as you might think. I ran a search on all the PCs in my house, and it was not on 5 Win7 and 4 WinXP systems all with loads of commercial and opensource software.
If msvcr100.dll was not part of MS's prior C++ Redistributable Packages (namely 2005 and 2008) then I suspect relatively few ppl will have it. Heck, Nero 10 and PowerDVD 10 (both released in the last 18 months) install the C++ 2005 Redistributable Package.
You will simply have dodged a hailstorm of requests as most Win users from the Humble Bundle sale will install Cogs (which does not require this dependency) and not Cogs Go. And those who do install Cogs Go will probably find it a lot easier to acquire the DLL via a search rather than go through the process of Registering, Authenticating and then searching the Forum here.
Anyway, thank you for an amazing game. I didn't know about it until I read about the Humble Bundle deal at Ars Technica.