How do I get an Epson scanner to work with an HP Pavillion?


I have an Epson Stylus DX8400 multifunctional device (including a scanner) connected via USB to an HP Pavillion DV 9000 running Windows Vista. The other day I installed the Epson software, including Epson Scan. When I tried to scan something, the above error message appeared:

"Cannot properly communicate with the scanner. The carriage unit may be locked depending on your scanner model. Make sure the scanner is properly connected and set up to scan. Then, turn the scanner off and back on again."

Did that.

I'd be grateful for any advise on how to fix this.