@Morusec did you try to disable spellchecking for GeanyVC by setting the language option to an empty string in the plugin preferences?
The posted warnings about aspell and voikkpo libraries are rather harmless and I even think the mixed slashes would work. But Enchant on Windows doesn't work with these libraries even if there are built and present, these two messages always appear and I didn't find a way yet to silence them.
I assume the real problem is that you simply doesn't have any dictionaries installed but spell checking configured in the plugin preferences.