It almost looks like files are missing, all that is in folder is, data folder, Avernum application and a Steam file. Already submitted a ticket with Steam and sent a Email to Spiderweb. I have all the Spiderweb games that Steam has and all work but Avernum 4 & 5.
Thanks.
Also, 6 and Escape from the pit come up with a configuration program, 4 & 5 do not.