If by the third door you mean from the Nexus Room, then you have entered the Hrebalist's House. there are 6 Dream Pieces in this room. They are located in the following places:
1) High up under the purple flowers next to the Nexus Gate
2) On the floor in front of the planter(flowerbox)
3) Inside on the bottom edge of the window above the front door
4) On the floor by the front door
5) On the floor in the spot of sunlight
6) On the window sill above the planter
 
When you go out the front door into the yard where the windmill is, the Dream Pieces are located in the following places:
1) In the window above the door
2) On the ground on the right side of the house bu the fence
3 + 4) on the ground to the right of the door
5) in the pathway going towards the windmill
6) On the left side of the right leg of the windmill
 
In the Garden where the Scarecrow is:
1) on the wall by the gate near the bottom of the screen
2) At the edge of the garden by the walkway
3) On the balcony ledge
4) Under the planting next to the unripe pumpkins
5) Under the planting to the right of the scarecrow (you will really have to pay attention to your cursor)
6) Next to what looks like a cabbage to the left of the scarecrow
 
Finally, in the kitchen:
1) Next to the fireplace on the floor
2) On the floor between the counter and the work table
3) Between 2 jars on the bottom shelf above the Fireplace
4) On the counter to the right of the sink
5) on the 3rd shelf next to the sugar to the right of the sinl
6) on the 2nd shelf next to the Flour to the left of the sink.
 
These are all the Dream Pieces for the Herbalist Area of the third Door from the Nexus Room. There are 15 areas that each contain 6 Dream Pieces. Some are extremely hard to find! If you need help for  other areas, I have a complete descriptive list of all 90 Dream Pieces. Just ask I will be glad to help!
 
SuzyQ

I can tell that you are upset, but, what Operating System are you running on you computer? Is it XP or Vista, or are you running Mac?
 
You may have to uninstall and then reinstall, and then it should be fine.
 
The other thing is, if you have the FirstPeek copy of this game, you will need to uninstall that as the copy you have of the full game will not work.
 
These are the instructions for Vista, but they are very similar to the steps for XP
 
1) Start
2) Control Panel
3) Uninstall a program
4) look for the FirstPeek Version of the game
5) Right click it and then click uninstall
6) Then look for the full Version of the game
7) repeat step 5
8) Close the windows and go to PlayFirst and redownload the game again
 
You should be able to play the game now.
 
I hope that this helps. I have found that if I have the FirstPeek Version still installed the Full version will not work!
 
Good Luck,
 
SuzyQ