This is helpful for anyone... please add it to the pastebin.
I have never had a problem with the game, and you won't either as long as you do a few things. Here are the steps:.
1. Use Hongfire's pAppLoc
This is super useful:
This allows you to right click on the desktop shortcut and choose "Run as administrator with Japanese locale". Far better than Microsoft AppLocale because it integrates with Window's right click UI. I use it. It's what people who want to play visual novels and ero games use.
2. Set your system time to Japanese time (GMT+9) but ONLY WHEN YOU INSTALL THE GAME FOR THE FIRST TIME OR ANY TIME YOU PATCH. You can change it back after you're finished, but if it ever asks you to patch, you need to set your time to GMT+9 or else the game will get stuck in the endless loop patch and redownload the game over and over. As long as you remember to do this when there is a patch, you will be OK.
3. Setting Japanese region/currency/etc not necessary on your computer if you're using pAppLoc or AppLocale.
4. It is not necessary to run the VPN when patching your client. It slows you down. Only use the VPN when playing the game.
5. Gundam does not use UDP, so TCP connections are fine.