Attached Link: http://www.3drender.com/light/EqTutorial/tiling.htm

I'm not sure what the names of everything are in Paintshop Pro, but here's how I did it in Photoshop. Selected an area of the picture that was 512x512 and cropped to that size, select Filter>>Other>>Offset and set the horizontal and vertical values to half the width and height (in this case, 256x256) You should then have something like the attached pic. Last use the clone tool to blend in the 'crosshairs'. When you're done, it should tile nicely. I also evened out the luminance of the picture before I started making the texture. Tutorial for that at the link. Hope this made sense, Rich