HELP with cursor creation/editing

[=Hellfire=]

Hey I tried to play a bit with the cursor.txm but it's harder as I thought or I just don't do the right thing xD

So, here is what I did so far:

- I opened the cursor.txm file in UTF editor
- Extracted the MIP0 node into .tga formate picture
- Opened this one in paint.net (i guess photoshop would work too)
- After having modified what I wanted different, without changing the size or position of the symbols used for the cursors, I saved this file, again as .tga file.
- I imported this changed texture back into the cursor.txm file, made a backup of the original one in the SCREENS folder and put the new one in it's place.
- Didn't touch the mousie.ini since it's setting the coordinates for the several cursors used.
- Open the launcher, start the game.

And here is where it get a bit weird:
- Game crashes as soon as it's supposed to open the menu screen...

Can anyone tell me what's wrong?