A similar issue occurs, if the FMU dll requires another dll which is not included in the FMU, or if the importing tool does not handle the dependent dlls correctly. So, you must make sure that the dependent dlls are available on the executing computer or in the FMU. You can also try to avoid dependencies by linking statically.

You can observe the dependency tree with the dependency walker (https://www.dependencywalker.com) or reimplementations of that tool (https://github.com/lucasg/Dependencies).

Visual Studio binaries depend on the runtime libraries (e.g. msvcr*.dll) if you set the switch "/md". If you set the switch "/mt" the dependency is linked statically to your library.