The problem is that your command is all in quotes, including the parameters.
Change
"C:\Program Files\NUnit 2.6.3\bin\nunit-console.exe Victoria.Tests.Integration/bin/Debug/Victoria.Tests.Integration.dll /xml=nunit-result.xml"
to
"C:\Program Files\NUnit 2.6.3\bin\nunit-console.exe" Victoria.Tests.Integration/bin/Debug/Victoria.Tests.Integration.dll /xml=nunit-result.xml