Error "The type initializer for 'Quest.Toad.Security.SecurityProviders' threw an exception" when (4313420)

The following error is displayed when attempting to launch Toad:

"System.TypeInitializationException was unhandled
Message="The type initializer for 'Quest.Toad.Security.SecurityProviders' threw an exception."
Source="ToadCore"
TypeName="Quest.Toad.Security.SecurityProviders"
StackTrace:
at Quest.Toad.Security.SecurityProviders.AnySecurity(IConnection connection)
at Quest.Toad.ActionManagement.UIActionEntry.ConnectionChanged(Object sender, ConnectionEventArgs args)
at Quest.Toad.ActionManagement.UIActionEntry.InitializeAccessControl()
at Quest.Toad.ActionManagement.UIActionEntry..ctor(Object instance, Hashtable submenues, ActionInvocationPoint invPoint, IUIInvocationPoint uiInvPoint)
at Quest.Toad.ActionManagement.ActionsRenderer.RenderExternalActions(IActionExtensible target)
at Quest.Toad.Gui.MainForm..ctor()
at Quest.Toad.StartupForm.LoadPlugins()
at Quest.Toad.StartupForm.Main(String[] args)
InnerException: System.FormatException
Message="Input string was not in a correct format."
Source="mscorlib"
StackTrace:
at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
..."