I havent give up yet...
But I'm running out of ideas and chances.
Right now, I'm logged as root in a terminal, running a Xubuntu Live CD.
The VL iso file is saved in a hard-drive partition already mounted with read and write permissions. Also, I have chmod 777 vinstall-iso and VL-5.8-std-Gold.iso.
So, I-m in the terminal, as root, and run './vinstall-iso VL-5.8-std-Gold.iso'.
And I get again:
"Error: must run as root.
Please, login as root or call su first"
I have tried calling su, and running the same command again, but nothing.
Also, switched to init 2, as the installation guide says, but it doesn't make any difference.
I'm about to give up until I get a new CD drive or until someone comes with a new way to install VL .
Thanks again vectorized people.