Confused am I...
So is it not a legitimated question to ask who gives Support for a software? For us, who are not familar with the different version history of Uplink for PC, Linux, Mac it's really confusing. And nowhere, only in the App Store, I found the version Number 1.6.5 before.
Again, I don't know what you are quoting above, but, as it says, IV are responsible for the App Store version.
Now, it seems that you actually wanted support, rather than to just complain about the lack thereof (perhaps you should have said so in the first place?):
I bought 1.6.5 in Apples App Store last week after trying the 1.6.1 Demo before. When I tried to install a custom Gateway, like discribed in many forums, I got the same Error Msg "An Uplink Asseration Failure has occ...". And after I read this thread here, I send my support request to Ambrosia, who then told me that Introversion supports 1.6.5.
If I understand correctly, you are trying to use a custom Gateway with version 1.6.5. I see no reason to assume that this should work (or that it shouldn't, for that matter). It is possible that version 1.6.5 is incompatible with custom gateways. I don't have 1.6.5, so I have no way of testing it out.
Finally, for the record, the error that you report ("An Uplink Assertion Failure") should mean that the game is in a state that it doesn't expect to be in. There are tons of reasons why this might happen, and there is no reason to expect that your error has anything to do with the original poster's error from two years ago.