1. Known issue when using a high-contrast colour scheme (and perhaps the Classic Theme as a whole?) In any case, here's what it's meant to look like, for reference:
Now you should be able to tell which button to click. I'll have to look into why it breaks like that sometime. Also, if you could tell me which version of the game you have, that'd be great.
2. Well...yes, the Launcher can't inject the mods' code into the game without knowing which version it is, and the automatic detection functionality seems to not be co-operating, and you've yet to tell it which version you have, so the game starts without anything injected, resulting in the error message not being hidden at startup.
Anywaves, let me know if you encounter any further issues.