dpkg-buildpackage problem.

Hi all debian users.I hope,everything is ok for you.
I have Debian 4.0 Etch stable and running some service on it.I want to download source package and build deb package.

I have been typing,

# cd /usr/src
# apt-get source xyz

and download "xyz_1.0.orig.tar.gz" , "xyz._1.0.diff.gz" and "xyz_1.0.dsc" and automaticly extract "xyz.orig.tar.gz" to "xyz-1.0" folder and I have been applying some patch and other things to xyz-1.0 and

# dpkg-buildpackage

and deb package is builded successfully :) I dont have any problem.

But i want to apply patch and create deb package for "xyz-1.2" so I searched and found "xyz_1.2.orig.tar.gz" , "xyz_1.2.diff.gz" and "xyz_1.2.dsc",
from source web page.
I have put them to /usr/src directory and extract "xyz_1.2.orig.tar.gz" to "xyz-1.2" folder.Again,i applied some patch and entered

# dpkg-buildpackage

but error was printed like this:

dpkg-parsechangelog: error: cannot open debian/changelog to find format: No such file or directory
dpkg-buildpackage: unable to determine source package is

Do i make wrong something ? or I have to type other command before dpkg-buildpackege,while create deb file without apt-get source command ?

After type apt-get source xyz for xyz_1.0,I saw this information,

dpkg-source: extracting xyz in xyz-1.0 *1
dpkg-source: unpacking xyz_1.0.orig.tar.gz *2
dpkg-source: applying ./xyz_1.0.diff.gz *3

I understand *1 and *2 but I can not understand *3 ? Should I do *3 manually,when i create deb file for xyz_1.2 ? and If it is true,what should i do for *3 step ?

Do i ignore some step while create deb file without apt-get source command ?

Thanks.

Iyi calismalar.Basarilar...
Semih Gokalp
Istanbul/Turkiye