Fixed it.
https://github.com/MinecraftForge/ForgeGradle/commit/a63e78585c3966db24a69aae950c4caf48cd0d25
Delete the eclipse folder, and then run "gradlew setupForge --refresh-dependencies"
that will ensure you get the latest ForgeGradle
If you are using FOrge 960+
-- this is a ForgeGradle problem.. which has been fixed. simply run the setup with --refresh-dependencies
If you are using Forge 953 or earlier
-- this is an MCP problem.
-- In your fml.py (forge/fml/fml.py)
-- -- line 1149 change to 'https://libraries.minecraft.net/'
-- -- line 1242 change to 'http://resources.download.minecraft.net'
thats is a very different problem.. not similair at all...
anyways.. you are trying to do your commands in a folder where there is no build.gradle file. you must be in the same directory as the build.gradle file.
#1) download and extract the src zip
#2) open command line in that folder
#3) run "gradlew.bat eclipse"
#4) Open eclipse, and point it to the eclipse folder as the workspace
#5) profit.