error 129 Disk storage unit full

Do I run this command on the media or master server? And what do I use for the string?

Are you saying the media server is not active because the disk is full?

What are retention levels on this dedupe disk?
Are backups getting duplicated anywhere else?

Have a look at this TN to understand expiration and data removal process from dedupe disk and how you can manually reclaim expired storage space. 
http://www.symantec.com/docs/TECH124914

We opened a ticket with tech support and this is what I sent to them.

This is what the is in  job details
---------------------------------------------------------------------------------
info nbjm (pid=8220) starting backup job (jobid=58769) for client splunk-1, policy VMWARE_DEV_DEV, schedule Diff-inc
info nbjm (pid=8220) requesting STANDARD_RESOURCE resources from RB for backup job (jobid=58769, request id:{3867C4B0-23B9-11E4-A63B-0010E020C290})
requesting resource masterserver-2.NBU_CLIENT.MAXJOBS. splunk-1
requesting resource masterserver-2.NBU_POLICY.MAXJOBS.VMWARE_ DEV_DEV
awaiting resource Dedupe_Winmedia01_STU.Waiting for resources.
Reason: Disk media server is not active, Media server: Winmedia01,
Robot Type(Number): NONE(N/A), Media ID: N/A, Drive Name: N/A,
Volume Pool: NetBackup, Storage Unit: Dedupe_Winmedia01_STU, Drive Scan Host: N/A,
Disk Pool: Dedupe_Winmedia01_DP, Disk Volume: PureDiskVolume
-------------------------------------------------------------------------------------

We found this, which you might find interesting.
Under Media and Device Management --> Devices --> Media Servers
Winmedia00 status is set to offline
Winmedia01 status is set to Active for Tape
All other media servers are set to Active for Tape and Disk.

We have a firewall called HBSS or ePolicy. They make changes from time to time that messes stuff up. So what ports do we need to have open in order to connect to the disk pools? The Disk Pools are on a NetApp device.

Are there commands can we run that check for connectivity between the Master server and the media servers or the Disk pools?

thanks I will read the technote. we are using only 22% of the disk pool space

we are using only 22% of the disk pool space

So, where is the 'error 129 Disk storage unit full' in your subject coming from?

The error is in the status, when we run the job. As you can see from the post above this one the The Windows media servers are showing that they can't reach the disk pool. My co-worker reran the GUI tool to change the status of the media server but the status didn't change.

You have not showed us any logs or Job details showing status 129.

Only 'Disk media server is not active' which is a comms problem.

NBU 7.5 and 7.6 needs port 1556 (PBX) only between master and media server.  

See NetBackup Network Ports Reference Guide 

Any chance the firewall is doing NAT or PAT? 
This is not supported.

I ran the nbdevquery -listdp -stype PureDisk -U and the all the pools show up

I ran nbdevquery -liststs -stype PureDisk -U and the pools show up

This is a Windows media sever and I was not able to find spoold or spad in the services list.

I asked the firewall guys and they say the firewall is down and there are no errors or blocks reported in the logs.