Final Cut Pro "Permission denied. Libraries require read and write permissions." iMac 27'

I have a few .fcpbundle which I'm unable to open in Final Cut Pro X. When I click get info, and check sharing and permissions, I'm shown the following.

You have custom access

Name Privilege

larryxxxx (Me) Read & Write

Staff Read only

Everyone Read only

Yet when I try to open it, I get a yellow triangle warning box which says, this document "xyzzy.fcpbundle could not be opened. Permission denied. Libraries require read and write permissions.

What causes this problem and how can I fix it so I can open my files?

Thanks

[Re-titled by Moderator]