I just tried this out on a test site running CMS R2 SP2 and Community 3.2 SP1 (with hotfix 1 and 2), and I got the same error.
Seems to be a bug in the EPiServer.Community.Web.Administration.ContestInfoControl.dataListSubmissions_UpdateCommand method where a User is added to a readonly UserCollection (instead of the UserCollection being cloned before adding the User, which would be the correct way of doing it). Could this be the case?
Yes, this is a known issue. I don't think the fix has yet been released as port of a public update, but Support has a fix available.
Used the code in the SDK to submit answers to a contest. The answers get submitted and can be viewed in the EPiserver Community Administration UI.
When clicking on the "Set as winner"-button on an entry, I receive the following runtime error:
Server Error in '/' Application.
Invalid use of read only object - Clone() it before making modifications.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.InvalidOperationException: Invalid use of read only object - Clone() it before making modifications.
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.
Version Information: Microsoft .NET Framework Version:2.0.50727.4927; ASP.NET Version:2.0.50727.4927
Is this a bug?