work flow instance error after migration to SP2013

hi,

Can any one suggest now.

We migrated SP2010 to SP2013 using content DB attach process.And deployed all the Custom components related to SP2010 in 2013 environment to both 14 and 15 hive folders.For the workflow on one of the list,its giving below error when we click on the list item task which got created after work flow triggered.

URL:http://Server:80/SiteTest/_layouts/WrkStat.aspx?List={9038BA6A-A39F-4A88-B831-A396FD2D077D}&WorkflowInstanceID={D01CD165-A94E-431A-B38A-001546346138}&Web=38586cd7-bae5-4a5d-b36d-808a913be34e

Error:

• <nativehr>0x80004005</nativehr><nativestack></nativestack>Updates are currently disallowed on GET requests.  To allow updates on a GET, set the 'AllowUnsafeUpdates' property on SPWeb.
  Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Runtime.InteropServices.COMException: <nativehr>0x80004005</nativehr><nativestack></nativestack>Updates are currently disallowed on GET requests.  To allow updates on a GET, set the 'AllowUnsafeUpdates' property on SPWeb.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. 

Stack Trace:

[COMException (0x81070e97): <nativehr>0x80004005</nativehr><nativestack></nativestack>Updates are currently disallowed on GET requests.  To allow updates on a GET, set the 'AllowUnsafeUpdates' property on SPWeb.]
   Microsoft.SharePoint.Library.SPRequestInternalClass.UpdateMembers(String bstrUrl, UInt32 dwObjectType, String bstrObjId, Guid& pguidScopeId, Int32 lGroupID, Int32 lGroupOwnerId, Object& pvarArrayAdd, Object& pvarArrayAddIds, Object& pvarArrayLoginsRemove, Object& pvarArrayIdsRemove, Boolean bRemoveFromCurrentScopeOnly, Boolean bSendEmail) +0
   Microsoft.SharePoint.Library.SPRequest.UpdateMembers(String bstrUrl, UInt32 dwObjectType, String bstrObjId, Guid& pguidScopeId, Int32 lGroupID, Int32 lGroupOwnerId, Object& pvarArrayAdd, Object& pvarArrayAddIds, Object& pvarArrayLoginsRemove, Object& pvarArrayIdsRemove, Boolean bRemoveFromCurrentScopeOnly, Boolean bSendEmail) +362

[SPException: Updates are currently disallowed on GET requests.  To allow updates on a GET, set the 'AllowUnsafeUpdates' property on SPWeb.]
   Microsoft.SharePoint.SPGlobal.HandleComException(COMException comEx) +146
   Microsoft.SharePoint.Library.SPRequest.UpdateMembers(String bstrUrl, UInt32 dwObjectType, String bstrObjId, Guid& pguidScopeId, Int32 lGroupID, Int32 lGroupOwnerId, Object& pvarArrayAdd, Object& pvarArrayAddIds, Object& pvarArrayLoginsRemove, Object& pvarArrayIdsRemove, Boolean bRemoveFromCurrentScopeOnly, Boolean bSendEmail) +1134
   Microsoft.SharePoint.SPUserCollection.UpdateMembers(Object objUpdateInfo, Object objAddIds, Object objRemoveLogins, Object objRemoveIds, Boolean fSendEmail) +548
   Microsoft.SharePoint.SPUserCollection.AddCollection(SPUserInfo[] addUsersInfo, IEnumerable`1 addUsers) +1253
   Microsoft.SharePoint.SPWeb.EnsureUser(String logonName) +365

Thanks &amp; Regards, Krishna