Checkerboard Scenery (Textures)

Hi. I have recently got a problem with my FS9 scenery. In stead of natural curwing borders beetween different types of texture, all sceneries now look like checkerboard. From a distance all edges between texture are almost straight lines. This is rather ugly. I have searched different forums to find an answer to what is causing this, but no luck so far. My computer is a Pentium 4, 2,5 GHz, with 1 GB RAM and Radeon 9700 PRO 128 MB Graphics card with the newest ATI Catalyst drivers. I thought it could be a problem with landclass sceneries, but all my landclass sceneries are for local areas, and my problem is affecting all sceneries, both areas with original FS Scenery and areas with addon sceneries. I will be thankful if anyone can help me.Best regards, Tor Arild Danielsen