Use NUnit Console Runner to run all tests under a folder

I am trying to use NUnit Runners 2.6.4 to run all test assemblies in my test folder. My current command looks like this:

/nologo /noshadow /framework:net-4.0 /xml:.\test\TestResults.xml .\test\*.Test.dll

Unfortunately Nunit just throws a System.ArgumentException: Illegal characters in path.

Is there anyway I can achieve this?