The BlueprintFileUtilsBPLibrary API is not accessible through python scripts run in the editor.
Attempting to run a script utilizing BplueprintFileUtilsBPLibrary results in:
This occurs in //UE4/Release-4.22 cl 8065155 so this is not a regression.
The Blueprint File Utilities plugin is no longer enabled in projects by deafult. It can be enabled by going to Window > Plugins and searching for 'Blueprint File Utilities'
The module is inaccessible
The module is accessible through python script
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-100724 in the post.