This article concerns Windows users only
The mentioned dll file is required by Sigmund to work.
It's very likely you experienced something called the dll hell, which is most commonly result of reckles approach of some developers to the contents of the System libraries folder. Files in the system folder can be updated or removed by an application's installer, which is not recommended thing to do, because it often leads to such issues.
It's very likely the required, but reported as missing, the msvcp100.dll exists your System directory anyway,
but its version can be outdated, or some of the dependant .dlls' versions are mismatched with msvcp100.dll due
to some third party software actions, making the dll unloadable.
To restore the order in the system's dlls and make Sigmund being loadable try solution from this FAQ entry.