can't scan with an epson rx620?

Hello:
I have an epson RX620. Everytime I try to scan from the computer, an error message appears: the scan can't be opened. I have tried all the help recommended and have also re-installed the program, apart from searching in epson's website for new drivers for the scan, but nothing works. As a printer, it works OK, both from the PC or without it. However, the scan is only working without the computer.