Try:
var dll_handle;
STRING* Pristina = "Pristina.TTF";
dllfunction InstallFont(MyFont);

void main()
{
dll_handle = dll_open("FontInstall.dll");
InstallFont(Pristina);

If that does not work, I'm afraid I can't help you...

Nevermind! Here's how to load and use a TTF font using lite-c with no .dll:

Step #1: Place the font in your game directory.

Step #2: At the top of your main script, make sure that you include windows.h:

#include <windows.h>;

Step #3: I'm not sure if this step is necessary or perfectly correct, but add the following to your main loop:

void main()
{
...
AddFontResource("Pristina.TFF");
}

Step #4: Include the font in on of your panels

FONT* mission_font = "Pristina#30";

TEXT* mission_text =
{
layer = 96;
pos_x = 10;
pos_y = 10;
size_y = 40;
offset_y = 0;
string (mission_text_string);
font = mission_font;
}

I just got this working 5 minutes ago, so I'm no expert at it. However, I wanted to share my thoughts with other lite-c programmers.

Thanks
- Bret