I want to change to content of that file, so I extracted it from Kotor Tool. It's the file where Carth talks to you for the first time since you crashed on Taris.
I changed what I want, and put it in my override.

After the cutscene of Bastila fighting a Dark Jedi, Carth begins to talk to you. But then there's a fade-in, and the screen stays black. I can here my PC walking if I use the arrows.

Then I saw that the first two lines in the Dlg file aren't in-game, so I deleted the node. I tried it again, but then the dialogue doesn't fire. I deleted the text in the "script that determines availability", and tried another time.

Now, Carth speaks to you, but instead of Carth or the PC you see the door, in blue, like you're watching it with a security computer. Carth only speaks one or two lines, before it ends again.

Can someone help with this?

errr...looks like you messed up with conditional scripts. Be careful when you delete entries in a dialogue file. You could try Tk102's dlgeditor: I think it's easier to use than Kotor tool's for this kind of thing.

But then again, you have to check each script you remove: they could be conditional scripts but there could also be some other important scripts such as those that set global variables: if you delete an entry you<re not supposed to, then you could break a quest.

I only used Kotor Tool to extract the dlg file, I have edited the file with Tk102's dlgeditor.

Where can I find the script which is attached to the entry?

You can use the view menu for additional display options. I like to use them for quick reference. (You can always look at the bottom of the screen too )

Before deleteing an entry that contains a script that determines its availability or where a script is fired, verify the content of the script. For some scripts you will find the source code in the BIFs (the.nss files) but for most of them you will only be able to view the byte code (.ncs) but even without knowing how to read the byte code, you can spot the functions that are used and get an idea of what the script does.

I could also change the script so that the entry doesn't fire... But then I have to mess with the scripts.

But, err, about the ncs files, can't I just try to decompile them, so I could read it with notepad or something?

Edit: The entry with which the dialogue should normally start, also has a conditional cript, which is fired after the last entry of the part of the dialogue which is normally not in-game.

What I could do, is let those entries in the game, so that they are actually in-game, but then I have to find a way to deal with the fade-in and fade-out problem...