I made it work!
I took the following steps:
1. I unistalled the drivers, deleted all the files that remained after the unistall and I cleaned the registry from all the references to the scanner that I could find (some of them manually, some of them by using CCleaner).
2. I updated my mainboard's BIOS (<--perhaps this step was crucial)
3. In BIOS, new options appeared which were not there previously. I turned on the Enhanced Parallel Port (EPP) option. Though the scanner can work in SPP mode, its better like this.
4. I uninstalled several programs, cause I assumed that they can interfere with the scanner. I unistalled: Corel Draw X13, virtual dvd drive, my mobile phone's software etc. (now I dont think that this step was necesary, but I wanted to achieve a more-less clean situation).
5. After achieving a more-less "clean" situation, I installed the scanner's drivers.
6. After the installation, I opened the ACDSee program, clicked import and the scanner was there!
7. I re-installed Corel Draw and the scanner is there! It works!
I dont know which of these steps was crucial, but I assume that the BIOS update helped.
The conclusion is: This scanner CAN work in Windows XP