Can anyone tell me when this game occurs in the series? Is it after 6? Is it somewhere in the middle?

Blades of Avernum is what we call a Gaiden. Due to it being a set of scenarios (and a level editor) the scenarios can take place whenever, wherever, and however the scenario writer pleases. This means it doesn't even have to take place in Avernum.

Ok thank you. I was under the impression it was perhaps another game in the series, but I guess not. I'll likely just move through the series and then check out Blades of Avernum eventually.