Naga Temple East - Bug Preventing admission to Prison room for key

[Wadoman]

I get to the prison room where the key is to get Whatsisname out of the cell below but even though the doors open and I kill off all the naga, I can't get in! It's like an invisible wall there. Anyone else encounter this? And if so, how to get rid of it?

Thanks for your help.

Steve

[Allain'45]

Try reloading an earlier saved game.
See what happens.

That's all I think for now!