Hi Thomas,
From my experience, this error means that it can't load the classes dynamically because something is missing, for one of the following reasons:
1. Do your classes use dlls? are they also always included?
2. Do your classes need any instrument drivers that aren't installed on the new machine, or (and this delayed us by months once!) the drivers in the new machine are not the same version as the drivers in the development machine?
3. Do your classes reference any external files?
4. Are you sure that your lvclass files are included in the build? Can you see them in the new machine? If you copy them from the new machine to the development machine, can you open them using LabView?
5. I'm sorry if this is a stupid question, but are you also including the lvclass methods? including an *.lvclass file will not necessarily include its methods (e.g. MyClass.lvclass::init.vi should also be included in the build, as well as any VIs that Init.vi would use)
How exactly are you loading the classes dynamically? Can you give an example? I assumed from your question that you are loading a specific VI from each lvclass dynamically, not using lvlibp (packed library).