I do have a problem using TMS 4.4.18 together with Denon AVR 3808. When I look at the device list I see a Denon AVR 4308 instead the 3808. When I change it to the right one it will kepp the setting for a while. After a restart it comes back with 4308. After another change to 3808 and a reload of the configuration site it still says 4308. Only a reset of the device list helps, until the next restart of the server.
I also tried to change the file permissions of the ini-file to read only - no success
TMS 4.4.18 running on a Dreambox DM800, Denon AVR 3808, same subnet
I had the same problem with TMS 4.4.18 running under Debian Linux