For importing the *.dbc file Dewesoft uses Visual C++ Redistributable for Visual Studio 2015.
If this is not installed, it can be downloaded from this link: https://www.microsoft.com/en-us/download/details.aspx?id=48145
Use the same version as Dewesoft:
Dewesoft 64-bit -> vc_redist.x64.exe
Dewesoft 32-bit -> vc_redist.x86.exe
The Visual C++ Redistributable for Visual Studio 2015 is also installed with Dewesoft X3 SP5 installer and newer.