VADP backups hanging

Hi All

We have an issue trying to figure out why the vadp backups are hanging

We are running the below config

The networker server is running Networker v8.1.1.2 build 280, windows 2008 R2

Most of the VM clients are running 8.0.0.4 build 204

The networker proxy servers are running Networker v8.0.0.4 build 204, windows 2008 R2

The vcentre server is running networker 8.0, VCentre server 4.1.0.17435, vsphere client 4.1.0.17435

Once the backup is started the below messages just keep cycling

09/25/14 14:36:17.811109  Sgrp_update_progress new : saving|5/0/0|5/0/0|

09/25/14 14:36:17.811109 Sgrp_update_progress old: saving|5/0/0||5/0/0|

There have been no changes to the environment and things worked fine before we saw the above error

I've also tried contacting the vsphere server using cli command

nsrvadp_modify_vm.exe -H -P https -u -p -l vm-name -k -c info) but that failed with the below error

(Its not getting to the snapshot stage):

The following internal error occurred unable to logon to vm server https//vmserver ip/sdk svc_vcs_networker details soap fault (v1.0) http error 400 bad request.

Any help on how to resolve or troubleshoot further would be helpful

Defence site so log files and information is restricted

thanks