Access Denied on some folders on Mac via AFP

We have a ReadyNAS 312 set up at our company. It has 5 shares set up (not including /backup and personal shares). User access is divided into groups. We are having an issue with one of our shares that all groups have access to, called /Resources. I am the admin and the sole user in a group called "Full Access". My assistant is in a group called "Operations_HR". When either of us mount the /Resources share, we have the little red "Access Denied" icons on some (but not all) folders. Other users, within other groups, have no problem accessing all folders within /Resources.

Below are some screenshots showing

1) Finder with Access Denied indicators

2) Network Access on this share, showing "FullAccess" as a read/write group

3) File Access on this share, showing 'FullAccess" as a read/write group

4) Just to confirm, my user account, showing me as in the "FullAccess" group.

I've logged in multiple times on multiple computers to verify there wasn't some permission caching issue going on as i tried various fixes.

My guess is that this may be related to who created certain folders and how, but i'm not sure why that would affect some groups and not others, if we both have matching "read/write" access.

Any thoughts?

My firmware is current, v6.4

Thanks in advance,

devin