cannot delete any files added to projectpier

Project:ProjectPier
Version:0.8.6-stable
Component:User interface
Category:support request
Priority:normal
Assigned:Unassigned
Status:new
Description

After clicking edit, ticking yes and putting in my password to try and delete a file, I get the following error message: "Failed to delete selected file".

I have researched this issue on this forum and have tried many things including:
1) changing my password
2) making sure 777 permission are in place
3) file system is set to File System, not database
4) making sure I have full permissions to access the project and subfolders

Nothing appears to be working. The file in question was a .pdf and I revised it to a .docx and I'm still having the same issue. This only appears to be effecting the deletion of files and folders. I am able to delete projects, tasks, etc.

I have the latest version of PP, MySQL and PHP.