UME permissions for Images Saver Action Block, MII version 12.1

I have a BLS using the Image saver block but it seems that some MII users can do not have the ablity to save files using this action block. The BLS transaction works fine when I'm logged in as MII admin.

What UME permissions do you need to write files on the local MII folder (in the project web path) to perform this action?

Note: I don't have access to UME on this box, as it is a customers box and is managed by a seperate basis person. I need to let that person know what permissions to add.