i just tested ur programm, if i set a static ip there comes an error. It seems like there is a problem setting the standard gateway cause the field on the left side is empty, everything else is set correctly. The settings are surely correct. My OS is Win 7 x64 Ultimate SP1.
i just tested Version 1.7 there it works. Sadly it is really slow compared to 1.8 :(
Maybe the information is usefull for u.
versions 1.7 and earlier use the netsh command to set the IP address and doesnt like it if you do not set a Default Gateway (this often is a problem with more than 1 network card). where 1.8 uses WMI to achieve this and you can leave the Default Gateway blank if that is required.
version 1.8 is still in testing as im not 100% sure on the restrictions with some operating systems when using WMI, and some programing errors my be hidden somewhere deep, im only human and there was a lot of code change around. also note that this language is a scripting language and not really designed to do these functions on its own. thats why I used netsh in the earlier versions and now WMI.