Rob (SkyDemon) here,
I should probably clarify that there were initially some serious problems with the GNS 2000 (early units were flawed in some way that I will not pretend to understand), but I understand that those have now been resolved by GNS themselves, or by the stockists who were trained to apply the fix.
I have a number of happy chaps who run the GNS 2000 with their iPads, but if anyone does have a problem, to contact GNS directly. You may have got one of the original batch...