I have the Sword of Gith. But everytime I click on the Gate, my character tries to unlock it in the normal way (he's part Bard). I've tried opening the door with the sword equipped & unequipped. I've given it to Safiya and tried to get her to open the door. Nothing seems to work. I'm not getting a message to 'try' the sword
I even tried after deleting everything in the overide folder.
I don't remember having this problem when I played with the original disks when the program was first released. Does anyone have a clue as to what I'm doing wrong? (I did do other things after meeting the Founder -- and letting her live)

Are you sure your at the right betrayer's gate?
The one in the lower vaults, and not the one in the upper vaults where you meet Kaelyn the Dove
Attempting to unlock it is usually a double click, a single click on the door should start a conversation with your companions.
The only conversation check, is if enemies are near, so make sure you've killed everything in the area.
If your at the right Betrayer's Gate and nothing else works, try the enabling the debug console and type
rs b08_a_betrayers_gate_opening

Thanks for the quick reply. Yes, I'm at the right place. the cursor is 'unlock', not 'select'. Don't get the conversation check. And there are enemies about -- shadows of the void -- on the other side of the gate.
Tried the 'opening' code; console says it was successfully sent, but nothing happens. PC continues 'unlocking' and getting 'specific key' message.

Can you right click on the gate and choose use or examine?
I don't know what else to suggest, other than asking here https://forum.neverwintervault.org/c/nwn2/6
kevL_s is very good at this sort of thing.

Tried both, no go. Even tried an earlier save (just before Myrkul) and reinstalling from GOG ... and my original disks (amazingly still had the key codes) ... something must be busted in the save game itself. Only thing I can think of is that I transferred in my 21 level Bard, Ranger, RDD from NWN2 (last time I played, I'm pretty sure it was at most a 20th level PC)
Really don't want to start a new game with a "newly-created" character. :(
Anyway, thanks for the link (forgot about NWNvault). I'll state my problem and see if anyone has any idea and can provide me with the codes to at least transport my party to next area.
Thanks again. Will keep you posted if anything happens.

Success!!! Again, thank you.
For the curious, the solution can be found at:

https://forum.neverwintervault.org/t/motb-betrayers-gate-wont-open/4065/12