Dungeon-be-gone is compatible with Improved Anvil; however, Improved Anvil's "Item Randomizer" program initiates in that area at the beginning of the game and it takes a few seconds before it can fully initiate (there are a relatively large number of variables which need to be set in that area). On slower computers it will take about 40 seconds (after the initial auto-save) for all of the variables to be set properly by the game's engine. On faster computers, it can be done faster. The point is that you should not rush to talk to that fellow and leave the area too quickly before all those variables are set. You don't need to do anything special, just stay in the area for (at least) 45 seconds (real time) and the variables will be set by the game's engine automatically. Then, you can talk to that fellow and leave the dungeon without any problem.

What happens if you didnt wait?

And are there any way to check this variables? Don't know what computer you call 'fast' (2Ghz CPU - is it fast enough?), but i definitely have spend very few time in dungeon.

If you are already in the middle of your game, you don't need to worry too much. The risk is low. When I tested it, I performed the test on a slow computer while another software was also running in the background doing its regular scan. It's even probable that the computer was lagging and that's why it took 40 seconds for all the variables to be set. I was actually testing it on an over-slowed system. Nonetheless, for future game-throughs, it's not bad if you just wait for about 45 seconds there before leaving the area.

As for your question, if the variables are not set properly, the "Item Randomizer" feature of the mod will not work as intended and in its full capacity. You won't face any critical bug.

Well I didnt see the robe of vecna or girdle of hill giant strength in the adventurer's mart. So I assume the item randomizer is working? And what happens if the item randomizer screws up? Will the items just disappear or something? I'm living for the day i see the robe of vecna again!

Ok, we tested this a few more times (with IA v4.3's item randomizer which is a bit bigger than v4.2's):

On a computer with 1.2 GHz processor and 256 MB RAM, it took 35 seconds for the randomizer to be initiated completely.

On a computer with 1.5 GHz precessor and 512 MB RAM, it took 26 seconds.

On a computer with 3.8 GHz processor and 2048 MB RAM, it took 24 second.

I will add a message which will be displayed on the screen in the first dungeon when the randomizer is initiated successfully, so that players who use dungoen-be-gone know when it is safe to exit the place. Leaving the area before seeing the message means that the randomizer is not turned on yet.