Sorry for bothering this part of the forum with newbie issues. Just wanted to tell that there seems to be a solution for my and maybe others' problems concerning this library:

On AVT's homepage I found the following:
The CFGCamera object of the MS VS C++ library FGCamera.lib could not be converted to MinGW compatible *.a library. That's why there's the C-wrapper FGWrap.dll providing the functions of the FireGrab interface to a camera handle instead of an CFGCamera object.
See here for details.

Thanks for your help.