Dealing with your Win98 machine, unusually, Epson recommend you plug the printer in, turn it on, and when "New Hardware" is recognised, point the computer to the CD for the drivers. This is opposite to the normal procedure for a USB device.
Did you load the drivers and software in that order?
Have you looked at the Epson site for a technical answer, as there is a wealth of information there? Also, Epson are regarded as having one of the best after sales services of any computer component manufacturer. If all else fails, a telephone call to them, may solve your problems.