When I used CorelDRAW and Photo-Paint 7, I used to bring in the images/scan them by going via: File>Twain in Photo-paint or coreldraw.
If you dont have a settings button/tab, or quivalent name, in the scanner software, to choose program to open what you have scanned, then I would probably see to that the scanned image at least got saved in a folder on my computer. And THEN open that image with Corel Photo-Paint 7 or CorelDRAW 7. One other thing, if you cant open the scanned image, then maybe there is a fileformat that Publisher, as you say, cant handle? If you scann as Tiff or Jpeg then you surely should be able to open it. My point is that start by just getting the image scanned, and saved in a folder, dont mind what program to associate/open with, if this is causing a problem. Just save it on your computer. And then start Photo-Paint/coreldraw, and then save it as you are used to, from within Photo-Paint/CorelDRAW.
Is it possible for you to get a scanned image, saved on your computer at all, with the scanner you use?
If not, then I would buy a new scanner. One can get very good scanner today. I use a Canon myself. And if you are fine with a Flat bed scanner, then there is a lot to choose from, for almost nothing.