If your game flow will be "linear" you might get away with hard-coded dialogs.
I suggest to make gaps in your Mode values though. Instead of (1, 2, 3..), use values (10, 20, 30...). This way, if in the future you decide to insert some additional dialogs between 10 and 20, you will not have to shift Mode values in your entire project.
If your game is non-linear, thing may quickly get out of control. I highly recommend using some dialog engine.
As for your troubles with the plugin - read comments to that post, there may be a solution.