[ale] beginer question about creating rpm file in red hat sistems

[Kresnik Igor]

Why i cant create rpm file? Im create tar file and put her in SOURCES 
forder. Program its writen with QT 4.3

if i  run comand  rpmbuild -bb calc.spec like ordinary user i get ansver
[igor at localhost SPECS]$ rpmbuild -bb calc.spec
Izvajanje(%prep): /bin/sh -e /var/tmp/rpm-tmp.32150
+ umask 022
+ cd /usr/src/redhat/BUILD
+ LANG=C
+ export LANG
+ unset DISPLAY
+ cd /usr/src/redhat/BUILD
+ rm -rf racunalo-1
+ tar -xf /usr/src/redhat/SOURCES/calculator.tar.gz
tar: calculator/button.cpp: Cannot open: File exists

 although in tar file this file exist? Next question its about %file 
section. In spec file i have writen
path for this file i get with command ldd program_name and i that path i 
write in spec file
/usr/local/Trolltech/Qt-4.3.0/lib/libQtGui.so.4
command  rpmbuild -bl calc.spec get me ansver
error: File not found: /tmp/calc/linux-gate.so.1
or i must get this file in folder /tmp/calc ?

 spec files for creating rpm

Summary: Racunalo!
Name: racunalo
%define version 1.0
Version: 1
Release: 1
License: GLP
Group: Applications/Editors
Source0: /calculator.tar.gz
Provides: IGOR
Prefix: /usr/calc
Buildroot: /tmp/calc

%description
Program for calculating number

%prep

%setup -q

%build

./configure CXXFLAGS=-O3 --prefix=$RPM_BUILD_ROOT/usr
make

%install

rm -fr $RPM_BUILD_ROOT
make install

%clean

rm -rf $RPM_BUILD_ROOT

%files
/linux-gate.so.1

Wher its error? Why i cant create rpm file?
Regards igor