if you type a number, say 1234 in the numeric keypad and then hit it takes you to preset 1234. Then you hit the button to select it.
If, however, after typing the number of the preset you hit (without hitting ) it tries to load the patch, but it doesn't. It stay on whatever patch was selected before.
I found two presets that won't load in VSig. These are 6413 and 6414.. they contain some kind of MIDI activity methinks that interferes with the transfer. Can you check these?