I had no trouble importing tilesets to rmxp, but with rmvx it seems a little different. I got the tileset, then went to the Resource Manager. I selected the Graphics/System folder, and clicked Import. After that, I did a Preview and it looks fine. However, I can't find how to actually use the imported tileset. I'm probably missing something really obvious, but I couldn't find the answer in a forum search or the Help files.