If you're not careful, and you have both versions of the .NET Framework on your box (1.0 and 1.1) NAnt will build your stuff using .NET 1.0. Whether that's what you want or not, it's important to be explicit.
There's two ways:
- Add <property name="nant.settings.currentframework" value="net-1.1"/> to your .build file(s).
or, to make the change to .NET 1.1 as the default, look in the NAnt.exe.config file in the same directory as NAnt.exe.
In this XML config file, in /configuration/nant/framework/platform[@default] you'll want to set that default attribute to "net-1.1" like this. Note: The ID "net-1.1" corresponds to a named <framework> section called "net-1.1" further down in the file that gives NAnt all the info it needs to build on that version. NAnt can also be used to build Mono, at least as of version 0.28 of Mono.
<platform name="win32" default="net-1.1">