These are the errors I noticed in the very beginning of the game.
minor:
Nouns are given in the old school format (Everything in Caps), but sometimes things are spelled normally a-la BW (Plus, the default names you're given are spelled normally, so you can't help but expect everything else to be normal). You should make this consistent. Either make all nouns normal or make them CAP-LOCKED. Don't switch back and forth.
Li's text after your battle with Jade is glitched.
Jade and Li's role switches back and forth. Li's a student, yet he's given Oak's Parcel (and his recycled text). Jade says that "you two" are going to fill the Pokedex, but she's the one who leaves, has the second starter, is the one who battles you, and is presumably your rival.
Recycled NPC text.
The trainer card should be changed to have a girl and so should the back sprite. Your card and back sprite are still Trainer Red.
The kid in the house with the scientist asks to trade your Alakazam for a Moltres.
Sometimes the text is too big and words get cut off.
The Pokedex is spelled pkDEX when Jade gives it to you.
Routes are called Wuste (is this German/Dutch?

)
definitely needs fixing
When losing a battle, you're transported to a placeholder house in Erdbeer. You're supposed to be taken to a) your house if you never visited a Pokemon Center. b) the last Pokemon Center you visited.
error! does not compute! GAME BREAKING!
You can buy the following:
Town Map for $101010
Escape Rope for $550
HM01 for $550 (but the clerk sells it to you for $0)
Pokedex for $0
Edit: For s*its and giggles, I actually purchased all that I could afford from that particular Mart (after save-stating of course). The Pokedex is useless since it just does the same thing the 'pkDEX' does while also taking up a slot in your bag. You can't throw it away. Same thing goes for HM01.
The starters are very uneven, stats wise:
Charmander is so weak that I die in a few hits and my attacks do little damage.
Squirtle is a bit stronger than Charmander and more often than not: wins when owned by your rival.
Bulbasaur is so haxed that he can kill you with 2-3 tackles.
Growl does damage, yet other moves such as Tail whip only effects stats.
The level curve is way too high and wild encounters are haxed out of proportion. If you chose Charmander or Squirtle, you would have lost to Jade and would still be level 5. Even with Bulbasaur at level 6, you'll still lose to wild Pokemon. All the Pokemon in the first patches of grass you encounter are levels 6-8 and all are powerful enough to kill you in 2-3 hits.
Wild Pokemon make you lose money if you lose to them. Not only this, but losing to them is the equivalent of losing to a trainer (1/2 your money).