source rpm error

[c c]

Hi

I downloaded MailScanner source rpm 
mailscanner-4.26.8-1.src.rpm    

Installed the src rpm package and then built rpm
package.

But when I installed the rpm package, I found the size
of the rpm file built from src rpm is different from
that in MailScanner-4.26.8-1.rpm.tar.gz  

Also I got error message during the installation. The
same error happened with verion mailscanner-4.23-11.
Here is the error

error: Failed dependencies:
        perl(Archive::Zip) is needed by
mailscanner-4.23-11
        perl(MailScanner::MCPMessage) is needed by
mailscanner-4.23-11

My environment is Redhat 9.0 on pentium IV.

I just wonder how the mailscanner rpm file in rpm tgz
file is created, from a tgz file or src rpm? If it is
from a tgz file, where is the tgz file located on the
web site?

If it is from source rpm, why do I get the error?

Thanks in advance.

-Tom

+++++++++++++++++++++++++++++++++++++++++++
[root at pe400 SPECS]# rpm -i mailscanner-4.23-11.src.rpm

[root at pe400 SPECS]# rpmbuild -ba MailScanner4.spec

[root at pe400 SPECS]# rpm -Uvh 
/usr/src/redhat/RPMS/noarch/mailscanner-4.23-11.noarch.rpm
error: Failed dependencies:
        perl(Archive::Zip) is needed by
mailscanner-4.23-11
        perl(MailScanner::MCPMessage) is needed by
mailscanner-4.23-11