Linux, Mapserver and ECW file

[Gianfranco Brescia]

Hi to all!
First I've to apologize for my English, I'm an Italian student of GIS.
My operative system is linux (Slackware 10.1)and I've installed mapserver
with gdal ad other staff...
My problem is that when I put a ecw file in the map file a cannot see it!
While the other raster file (tiff for example render very good), the ecw
file render nothing. I've the world file with the ecw file and the path is
right.
Is ecw a native support for mapserver or do I have to install staff like
erMapper: if so can someone tell me a how to install it with gdal; I've
read some in internet but seem to be a little difficult.
Thanks very much and sorry again for bad English.
Gianfranco.