Edit Code Club - The given key was not present in the dictionary.

[MacsDickinson]

This error is thrown when trying to edit this event:

http://www.yorkshiredigital.com/admin/event/code-club-mar-2016

Error details:

https://app.getsentry.com/yorkshire-digital/yorkshire-digital-website/issues/113855242/

KeyNotFoundException: The given key was not present in the dictionary.
  Module "Nancy.Routing.Route+<>c__DisplayClass4", line 81, in <Wrap>b__3
    System.Threading.Tasks.Task`1[System.Object] <Wrap>b__3(System.Object, System.Threading.CancellationToken)
  ?, in CallSite.Target
    System.Object CallSite.Target(System.Runtime.CompilerServices.Closure, System.Runtime.CompilerServices.CallSite, System.Func`2[System.Object,System.Object], System.Object)
  Module "YorkshireDigital.Web.Admin.Modules.AdminEventModule+<>c__DisplayClass3_0", line 525, in <.ctor>b__5
    System.Object <.ctor>b__5(System.Object)
  Module "YorkshireDigital.Data.Services.EventService", line 7, in Save
    Void Save(YorkshireDigital.Data.Domain.Events.Event, YorkshireDigital.Data.Domain.Account.User)
  Module "NHibernate.Impl.SessionImpl", line 25, in Evict
    Void Evict(System.Object)
...
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