antys, I think we might have a "solution" on the clash with SFC. I found an old thread describing the same problem and I guess there hasn't been a fix. Well anyway, as described here, we can do an ugly fix commenting out those two lines in nggfunctions.php.
line 417 : $GLOBALS['nggShowGallery'] = true;
line 427 : $GLOBALS['subalbum'] = true;
Although the line numbers seems to have changed a bit and I found it on 431 and 441.
I think it works for now (need to test SFC as well), but as always remember to repeat the procedure if you're updating the plugin (unless NGG fix this issue in upcoming releases).