I created a multiplayer game with all six characters.
I am playing by myself
All of a sudden... the characters are not gaining hit points
appropriately!! How frustrating!

The fighter gains three only per level when he should be gaining 15!!
It's the same for all 6 character classes. None of them gains more
than 3 per level.

PLEASE do not tell me that I'm going to have to restart after
installing some patch!

Actually, tell me the truth. Is there anything I can do??

No you need only more information. Until lv 10 you gain always 1-12hp+bonus;depends what class you have. When you reached the 10th lv you will now always get only 1-3 hp, when you level up.

This is completely unexpected.

So I won't be losing any abiltity relative to fduture quest requirements if I continue as I am?

In other words, this has been factored into the gameplay already?

Where is this mentioned in the manual?
Is that what the "hit dice" from the chart means??

If so, won't my fighter gain even more points as he progresses?

Additionally, why bother spending points on COn in char setup if your character will soon no longer need them for HP purposes.

Thanks for the info though.

Well any extra hp is important! Believe me. In some battle i survived with only 2-3 hit points, man i had so much luck. Con is really important, especially for fighters. And the hp gain when youre higher than lv 9 is also important. I think fighters with const 18 get then 4 hp every lv up. Until lv 10 you will approximately have ~90 hp and bevore you will reach the exp cap, there are other ~30 hp (all depends on which class you have) waiting for you. More Information you can get at:
http://www.planetbaldursgate.com/bg2/
Just look at the tables and character information, you will find what you need, i hope

you can find it in the manual
it says
level 1: 1d10
L2: 2d10
L3: 3d10
...
L10: 10d10
L11: 10d10+3

so you wont get another dice only the +3