I actually have one of these. Not a wonderhorse. Plagued by a third party software package and deliberate NO NETWORK policy. I have seen streaks and generally they are caused by foreign objects on the glass or other scanner parts.

However, it could be a sensor starting to go, memory failure, or even an issue with the driver.

Is movement smooth with a repeating cadence during scan? Do you have a piece of paper from a previous paper jam floating around inside? Try some canned air.

Also try scanning COLOR photographs at high resolution and see if the error stays in the same place. If it does look for optical problems from glass to scanner. Reinstall your drivers.

Good luck!