Error, "Index and count must refer to a location within the buffer" stepping over a call statement (4227126)

When debugging a stored procedure and when stepping over a call statement, the following error occurs:

System.ArgumentOutOfRangeException: Index and count must refer to a location within the buffer.
Parameter name: bytes

Stack trace:

   at System.Text.UTF8Encoding.GetString(Byte[] bytes, Int32 index, Int32 count)
   at Quest.Toad.Sybase.Debugger.SybaseSADebugProvider.ConvertToString(Byte[] byteArray)
   at Quest.Toad.Sybase.Debugger.SybaseSADebugProvider.CallVariableValue(Int32 callFrame, Int32 index)
   at Quest.Toad.Sybase.Debugger.SybaseSADebugProvider.GetAllWatchesImplementation(ContextType contextType, Int32 contextLevel)
   at Quest.Toad.Debugger.DebugProviderBase.GetAllWatches(ContextType contextType, Int32 contextLevel)
   at Quest.Toad.Debugger.DebugClient.GetAllWatches(CodeLocation lastLocation, ContextType contextType, Int32 contextLevel)
   at Quest.Toad.Debugger.LocalWatchesControl.GetWatches(CodeLocation location)
   at Quest.Toad.Debugger.WatchesControl.RefreshWatches(CodeLocation location)
   at Quest.Toad.Debugger.LocalWatchesControl.DebugStop(Object sender, DebugExecutionArgs args)
   at Quest.Toad.Notification.NotificationManager.DebugStopHandler.Invoke(Object sender, DebugExecutionArgs args)
   at Quest.Toad.Notification.NotificationManager.DebugStop(Object sender, DebugExecutionArgs args)
   at Quest.Toad.Debugger.DebugClient.ExecutionFinished(IDebugProvider provider, DebugExecutionArgs args)