Well, as it was an ISO image, there was no disk drive to blame. So I burned that ISO into a CD, boot my PC from it and tried to install Linux Mint into a free partition. The same problem happened at the same time during the installation problem. So the cuase of the problem was the ISO image.
And that faulty installation was not the only problem with this faulty ISO image, here is the list:
- when Gnome desktop loaded, an error poped up saying a problem prevented the clock applet from running;
- the desktop did not recognize nor auto-mount a flash card inserted in the reader;
- the removable drives and media preference dialog returned an error: "Volume manager not supported. The "hald" service "not currently running" enable the service"
- lspci command also returned an error: "I/O error at /usr/share/misc/pci.ids, line 0"
After the ISO was downloaded, I checked its MD5 signature with Nero MD5 Verifier (there are more alternative tools for checking this).
Now everything worked fine, I could install Linux Mint into a virtual disk and into a real partition without any of the problems mentioned above. Talk about a faulty download, jeez!