[Error] V-126-3 'bmrprep' could not complete the requested operation

Check the logs

TROUBLESHOOTING:
1. Enable bmrprep log on the BMR Server.
vxlogcfg -a -p 51216 -o 126 -s DebugLevel=6 -s DiagnosticLevel=6

2. Perform "Prepare to Restore" and once it fails collect the bmrprep log by running following command.
vxlogview -i 126 > /tmp/bmrprep.log

Hi, Thanks :)  Its a bug  in NB 7.6.0.3. Symantec support team is working on that.

Oh dear, is part of a BMR P2V? I know they fixed a bunch of issue related to that in 7.6.0.2

Please post all the details so others don't have to struggle before knowing to call for the EEB (once released) please.

The error is one recently encountered by BMR support. I was the BL engineer that worked on it.  See this article which I wrote for details on the root cause: 

BMR restores fail for backups taken after 7th September, 2014 when using non-Windows Master Servers 
http://www.symantec.com/docs/TECH225001 

It is important to note that the error affects all currently released versions of BMR. An EEB fix file is available for the following releases:

7.5.0.6
7.5.0.7
7.6.0.1
7.6.0.2
7.6.0.3

This also includes versions for Appliances.

If you encounter the issue, contact NBU support and ask for the appropriate version of fix for ET3624717. If you are at the the latest release, you can access the fix by checking the entry in the Late Breaking News (LBN) section of our on line documentation. The version for 7.6.0.3 can be directly downloaded from there without the need for a support call.

Thanks Jaime

Please don't EVER attach EEBs to a Connect reply!

If you need it, please download the public hotfix attached to this document:

BMR restores fail for backups taken after 7th September, 2014 when using non-Windows Master Servers
 http://symantec.com/docs/TECH224758