post processing problem has ruined my project

I suddenly got this problem

AppData/Local/Unity/cache/packages/packages.unity.com/com.unity.postprocessing@2.0.10-preview/PostProcessing/Runtime/Effects/LensDistortion.cs(51,50): error CS0117: UnityEngine.Rendering.PostProcessing.ShaderIDs' does not contain a definition for Distortion_CenterScale’

Now no scripts will run.
Iv tried re-importing standard assets and also tried deleting com.unity.postprocessing@2.0.5-preview
no luck.

Desperately need someone to explain to me whats wrong and how to fix it

fixed it…
instead of re-importing standard assets, I deleted standard assets from the scene then re-imported standard assets from the asset store
Immediately all scripts started running fine.