Irrlicht Engine

When i try to load .x to my program, there are error message "Only uncompressed x files currently supported".
My question, are there some code to uncompressed this file in Irrlicht???

What's usually that make the frame per second decrease ?
Before this, i try to run my program, and the fps > 300 but know i run the program the fps just = 4, what should I check first to solve this problem??

int fps = driver->getFPS();
if (lastFPS != fps)
{ core::stringw str = L"";
str ...

when i run this code, the first xml data was replaced by the second xml data, and the second replaced by the third, how i can make the xml data that the previous data will not replace by the newest one??

thank you...

I get something trouble when I used this
writer->writeElement(L"CharacterName",false, L"value", characterName);

where characterName is variable that used to save text...
core::stringw characterName = "Hai";

but when I use this
writer->writeElement(L"CharacterName",false, L"value", L ...

I have some data, the type is stringc.

data3 = found2->getText();
const char *c_str3 = data3.c_str();

for example the type variable data3 is stringc, and there are 5 others the same type data, I want to write the value from the variabel using xml writer..
I already open the manual but i don't ...

Sorry 4 bad english... I already make some 3d visualization , and to rendering the terrain i use class and constructor using IEventReceiver and in the same file i make user interface, and detect some button clicked.
In the terrain function i use
// create event receiver
MyEventReceiver receiver ...

What do you mean with ICompassSceneNode, i could't find it...
Where i can found the tutorial and the library? I really new in this case...

while(device->run())
if (device->isWindowActive())
{
driver->beginScene(true, true, 0 );
SMaterial m;
m.Lighting = false;
driver->setMaterial(m);
driver->setTransform(video::ETS_WORLD, core::matrix4());
driver->draw3DLine(vector3df(0,0,0),vector3df(1,0,0),video::SColor(255,255,0,0 ...

it's that true?? but i still can't see my line...

I still can't see the line... whereas i did your suggestion to write between while device run etc....

Would you like to give me the way to create the line per frame ? I dont know how to create that?

I've made a speedometer but the needle can't be seen??what am I supposed to do??Please help...
Here's the my source code :

video::IVideoDriver* driver = device->getVideoDriver();
gui::IGUIEnvironment* env = device->getGUIEnvironment();
driver-> draw2DLine (position2d <s32> (20, 20), position2d ...

I already made the picture,,what should I do next??
How does I make it??
I don't have any idea how to make it...

Yups... i want to make speedometer... How can i create it??