Deb package Installation Error while installing customized ubuntu server iso

Question

While I am trying to install a deb package embedded inside customized Ubuntu server ISO file, I get an installation error saying:

An installation step failed. You can try to run the failing item again from the menu or skip it and choose something else. The failing step is: Select and install software.

When I exclude the deb package everything seems to work perfectly. At first I thought it was a dependency problem but I am certain all the dependencies copied to the ISO file. Another opinion I got is maybe there is something wrong with deb package while creating it but it could be installed on command line without any problem. The steps I followed How to create a Customized Ubuntu Server ISO? while creating the ISO file.

Maybe am I missing something ?

EDIT: I think system tries to download the package from system repositories then says "Unable to locate the package" and doesn't recognize the folder extras I created so it can not find the package.

But I solved it in a different way. I created a local repository then installed packages and everything worked perfectly yet still don't know how to solve the first problem. The steps I followed:

1. First I created necessary folders

   mkdir -p ~/Downloads/newIso/dists/stable/extras/binary-i386 ~/Downloads/newIso/pool/extras/
   sudo cp ~/Downloads/*.deb newIso/pool/extras/
   

2. Then created Packages.gz which includes info of packages

   cd ~/Downloads/newIso
   sudo apt-ftparchive packages ./pool/extras/ | gzip -c > ./dists/stable/extras/binary-i386/Packages.gz
   cd ~/Downloads/
   

3. And added following line to the pre-seed file:

   d-i pkgsel/include string PACKAGE_NAME
   

   BTW I also tried without changing the pre-seed file just to see if the system searches extras/binary-i386 folder for packages.

4. Finally I created the ISO file:

   sudo mkisofs -J -l -b isolinux/isolinux.bin -no-emul-boot -boot-load-size 4 -boot-info-table -z -iso-level 4 -c isolinux/isolinux.cat -o ./ubuntu-14.04-myowninstall-amd64.iso -joliet-long newIso/
   

5. After installing system packages the installer says:

   An installation step is failed …

   After I looked at the debug logs, I saw:

   Unable to locate PACKAGE_NAME