I've installed the SDK 1.4 on the same Windows Server 2003 R2 server that Solarwinds is installed on with out any issues. I can use the PowerShell script example and the SWQL Studio with out issues however when I try the .NET example and browse to the https://servername:17778/SolarWinds/InformationService/OrionBasic url I get prompted for my credentials (which I enter in) then I get a HTTP 400 Bad Request error.
I've looked in the Orion.InformationService.log file but don't see any errors.
Any thoughts on what might be causing the URL not to work?
That URL (https://servername:17778/SolarWinds/InformationService/OrionBasic) is expecting you to POST a valid SOAP request, so your browser gets a 400 Bad Request error when it just tries to GET the URL.
To check connectivity in the browser, try loading https://servername:17778/SolarWinds/InformationService and see what happens. You should get an autogenerated page.