This was probably fixed as part of BZ #1196136. It needs to be tested.

It cannot be verified in vt14. I'll wait for next 3.5.1 vt build to verified this.

Got error while upgrading vt13.15 to vt14.1:
[ ERROR ] Failed to execute stage 'Setup validation': 201

details -> the same problem in bug: https://bugzilla.redhat.com/show_bug.cgi?id=1196136

It has already been addressed by https://gerrit.ovirt.org/#/c/38895/

if this bug failed qe, it should move to ASSIGNED/FAILED_QA and not MODIFIED.
please update bug accordingly.

Verified in rhevm-3.5.1-0.3.el6ev.noarch (vt14.2). Upgraded from rhevm-3.5.0-0.32.el6ev.noarch (vt13.11).

Verification steps followed steps to reproduce from comment 0: 
1. Install RHEVM 3.5.0 (vt13.11).
2. Start creating a template.
3. Stop ovirt-engine service
4. Run engine-setup to upgrade to 3.5.1 (vt14.2).

Result:

          Please confirm installation settings (OK, Cancel) [OK]: ok
[ INFO  ] Cleaning async tasks and compensations
          The following system tasks have been found running in the system:
          Task ID:           9e2f4bd5-2f6e-414c-9c4c-a0f6e0e4d239
          Task Name:         AddVmTemplateCommand          
          Task Description:  Adding a template             
          Started at:        30
          DC Name:           dc34                          
          The following commands have been found running in the system:
          The following compensations have been found running in the system:
          Would you like to try to wait for that?
          (Answering "no" will stop the upgrade (Yes, No) yes
          Waiting for the completion of 1 running tasks during the next 20 seconds.
          Press Ctrl+C to interrupt. 
          Waiting for the completion of 1 running tasks during the next 20 seconds.
          Press Ctrl+C to interrupt. 
[ INFO  ] Checking the Engine database consistency
[ INFO  ] Stage: Transaction setup
...
...
[ INFO  ] Execution of setup completed successfully

I found an issue with upgrading from latest_av:

          Please confirm installation settings (OK, Cancel) [OK]: 
[ INFO  ] Cleaning async tasks and compensations
          The following system tasks have been found running in the system:
          Task ID:           aa197e14-a2ec-476e-9930-94ddb64a1a27
          Task Name:         AddVmTemplateCommand          
          Task Description:  Adding a template             
          Started at:        30
          DC Name:           Default                       
          Task ID:           70bc0a87-8faf-4fbe-ad84-b348baf39ee6
          Task Name:         AddVmTemplateCommand          
          Task Description:  Adding a template             
          Started at:        30
          DC Name:           Default                       
[ ERROR ] Failed to execute stage 'Setup validation': 
[ INFO  ] Stage: Clean up
          Log file is located at /var/log/ovirt-engine/setup/ovirt-engine-setup-20150407124637-s1qm17.log
[ INFO  ] Generating answer file '/var/lib/ovirt-engine/setup/answers/20150407124658-setup.conf'
[ INFO  ] Stage: Pre-termination
[ INFO  ] Stage: Termination
[ ERROR ] Execution of setup failed

Setup failed after confirm installation settings
I used these steps:
1. Install latest_av
2. Start creating a template.
3. Run engine-setup to upgrade to 3.5.1 (vt14.2).

2015-04-07 12:46:58 DEBUG otopi.context context._executeMethod:152 method exception
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/otopi/context.py", line 142, in _executeMethod
    method['method']()
  File "/usr/share/ovirt-engine/setup/bin/../plugins/ovirt-engine-setup/ovirt-engine/upgrade/asynctasks.py", line 454, in _validateAsyncTasks
    compensations,
  File "/usr/share/ovirt-engine/setup/bin/../plugins/ovirt-engine-setup/ovirt-engine/upgrade/asynctasks.py", line 305, in _askUserToWaitForTasks
    commands='\n'.join(runningCommands),
TypeError
2015-04-07 12:46:58 ERROR otopi.context context._executeMethod:161 Failed to execute stage 'Setup validation'

attached logs

I tested vt13.11 too and there isn't any issue

Created attachment 1011693 [details]
engine-logs

When I tested upgrading from latest_av >> vt14.3
I tried to interrupt (with ctrl + c) waiting for task completion. Execution of setup failed as I expected but after that, rhevm webadmin was turned into ovirt webadmin (It looks like oVirt)

I suppose it's not the expected behavior. I noticed that the turning of webadmin theme happens before executing the configuration preview.

--additional info--
Attached screenshot

Created attachment 1014383 [details]
screenshot

(In reply to Petr Kubica from comment #9)
> When I tested upgrading from latest_av >> vt14.3
> I tried to interrupt (with ctrl + c) waiting for task completion. Execution
> of setup failed as I expected but after that, rhevm webadmin was turned into
> ovirt webadmin (It looks like oVirt)
> 
> I suppose it's not the expected behavior. I noticed that the turning of
> webadmin theme happens before executing the configuration preview.
> 
> --additional info--
> Attached screenshot

Please track this issue in a separate bug. I guess that the rhevm-branding got upgraded from 3.4 to 3.5 and not rolled back when interrupting the setup.

Verified in rhevm 3.5.1-0.4.el6ev (vt14.3)

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHSA-2015-0888.html