The problem comes from incompatible dependencies on the same package. web_ui is looking for logging package in pub and buckshot is looking for logging in dart:sdk.
Some times ago, SDK packages have been moved on pub.dartlang.org.
The hosted version of buckshot looks quite old (0.1.3) and does not handle that modification. However, the last version of the project on github does. So you can use the most recent version of Buckshot use the following dependencies :
dependencies:
hipster_mvc: 0.2.2
web_ui: ">=0.2.10 <0.2.11"
buckshot:
git: git://github.com/prujohn/Buckshot.git