Error loading external stack

[Pistris]

Am having difficulty loading a stack on a web server
am using the following line of code

go to stack URL "http://xxx.xxx.xxx.xxx/testfiles/internetstack.livecode"

now if I change the filename to internetstack.txt it loads it no problems

like this

go to stack URL "http://xxx.xxx.xxx.xxx/testfiles/internetstack.txt"

any thoughts?

am using IIS on the web server

[Pistris]

Sorry just realized I had to add the extension livecode in IIS