lubuntu - Using disk image files (.iso) as a repository

I am currently using Lubuntu 13.10 and I have made an iso file with AptonCD to backup the programs (with their dependencies of course) that I may need when I reinstall Lubuntu. My problem is that I am using a netbook and thus I have no CD or DVD reader. Thats why I cannot burn the iso file to a CD or DVD and plug it in to use it as a repository. Is there a way to use the iso file directly as a repository? I know that this question has already been answered in How to use a .iso image as a CD-ROM Repository? however when I run sudo apt-cdrom -d=/aptoncd-mountpoint add as posted in the answer of the former question I get

Using CD-ROM mount point /cdrom/
Unmounting CD-ROM
Waiting for disc...
Please insert a Disc in the drive and press enter
Mounting CD-ROM...
E: Failed to mount the cdrom.
E: No CD-ROM could be auto-detected or found using the default mount point.

I strongly believe that I have not done anything wrong. So what I wanted to ask is:
How can I fix this if possible? and How can I use an iso file as a repository if I am not able to do the steps presented in the answer of How to use a .iso image as a CD-ROM Repository? Thanks in advence