Edit: It looks like the tool in question has a specific allowance in the license to allow you to package the tool as-is like NAnt does. Still, could you use a different license that won't make the lawyers all jumpy?
I know I'm gonna get scorched for this, but I hate the GPL "Viral" OSS license. My team is looking at some technical alternatives for an integration issue. One of the more promising alternatives turned out to have a dependency on a GPL-licensed solution. No lawyer worth his/her salt is going to let you use any OSS tool licensed under the GPL. I know it was an idealistic thing, but in the real world the GPL just makes your code unusable inside of any commercial (read most) endeavors.
I very specifically licensed StructureMap under the Apache 2 license to make sure it could be used without restriction. I'd much rather that people actually use StructureMap than conform to the GPL's idealism. It's not like I'm ever going to make a dime off of it anyway.