In 10.5.5, the printer app will show up in your dock when a print job is sent to queue. Open the dock icon for the printer and see if the job shows and whether anything is preventing it from printing like it's paused or stopped.Leopard does require new drivers from Epson. Did you download those and install?
Those are the correct drivers.Open System Preferences / Print & Fax / Printing tab. Click Epson R2400, remove it with the minus sign just below. Then click the plus sign and put it back in via the dialog box. Try that first. Like refreshing the chosen driver.