Shunra Issue in ALM 11.52

Hi, After migration of ALM from 11.00 to 11.52, Shunra doesn't work properly. For example, if a test setup is done for a Single scenario and 1 Load Generator where WAN emulation is done using Shunra, it works fine. but fails for multiple scenario and users with Shunra. It displays the below error. But we do have latest license fixed:

"Error occurred while trying call 3rd party license component. Error Message: 4006 Unable to check the License out. Reason: The feature 'Maximum number of concurrent Load Generators' is not allowed by the current license. The license expiration date is Expired: 2014 4 17 10:31:6. (SHUNRA 8.61.000.71 error 04006 at LIC-001-00321)"

Is there any other license limtations or project limitations?Please advise the cause and resolution for this.

Thanks,
Manimozhi