[1.7.10] version 1180: FileNotFoundException: {ASSET_INDEX}.json

In 1.7.10, whenever I try to run Minecraft, I get this error:

Exception in thread "main" java.lang.RuntimeException: java.io.FileNotFoundException: C:\Users\Technostar\.gradle\caches\minecraft\assets\indexes\{ASSET_INDEX}.json (The system cannot find the file specified)

at com.google.common.base.Throwables.propagate(Throwables.java:160)

at GradleStart.setupAssets(GradleStart.java:273)

at GradleStart.startClient(GradleStart.java:81)

at GradleStart.main(GradleStart.java:55)

Caused by: java.io.FileNotFoundException: C:\Users\Technostar\.gradle\caches\minecraft\assets\indexes\{ASSET_INDEX}.json (The system cannot find the file specified)

at java.io.FileInputStream.open(Native Method)

at java.io.FileInputStream.<init>(Unknown Source)

at java.io.FileReader.<init>(Unknown Source)

at GradleStart.loadAssetsIndex(GradleStart.java:279)

at GradleStart.setupAssets(GradleStart.java:217)

... 2 more

What is this {ASSET_INDEX} file that I seem to be missing, and is there any way to fix this?