you don't need a key. i think you did something wrong..i'm so sorry!!

Yes, you do need the key. The key leads to the door, which leads to the toolbox.
Here's a walkthrough:

http://disneyinteractivestudios.custhelp.com/app/answers/detail/a_id/3163/session/L2F2LzEv
c2lkLzd3blJadVFq #1

I'm stuck there too. could someone help me . PLEASE!!!! I despately need it where is this
key!!!

When you find Perry the Platypus in the factory, go to the left of the "Scraps Box" near
him and run and jump on to the Moving Belt/Conv. Belt and jump onto the next platform,
then the next belt, then the next platform. Find the ladder on the right and climb it.
Instead of going up the next ladder (Or jumping onto the next platform), keep going right
after you climbed up the first ladder and you will find a computer. Switch to Ferb and fix
it. Then go past the box that was moved and search the "Scraps Box". You will find some
small keys. Use it to fix the doorway and go through it. (And fix the "Elevator Pad" next
to it if you want.) Sorry if I confused you.

P.S. YES, I am the same one that posted this. That is why it starts with Perry, not the
computer.

I cant find it either!!!

i cant even fid the first red box plzzzzzzzzzzzzzzzz help!!!!!!!!!!!!

i cant find the motor or the mimi engine plzzz help

i cant find even find the basketball shoes can someone plz help plz help me

YOU HAVE TO BE ON WORLD 2 TO FIND THE BASKET BALL SHOES

The key is in the scraps right in front of the door

How do you get the last tool box in the factary [world 1-4]

wheres the front of the door

The one user posted this:

When you find Perry the Platypus in the factory, go to the left of the "Scraps Box" near
him and run and jump on to the Moving Belt/Conv. Belt and jump onto the next platform,
then the next belt, then the next platform. Find the ladder on the right and climb it.
Instead of going up the next ladder (Or jumping onto the next platform), keep going right
after you climbed up the first ladder and you will find a computer. Switch to Ferb and fix
it. Then go past the box that was moved and search the "Scraps Box". You will find some
small keys. Use it to fix the doorway and go through it. (And fix the "Elevator Pad" next
to it if you want.) Sorry if I confused you.

I have not been able to run and jump onto the conveyor belt that is mentioned above. Is
there some trick to getting onto that conveyor belt. I always fall short. Thanks.

no dont sart the game over go to the gold tool box then you find keys

HOW DO YOU DEFIT DR DOFINZHIZ?

I DIDNT USE THE KEY YOU JUST GO LEFT WHEN U SEE THE FACTORY OR THE SPACE THING
TO GET U HOME.