I think I've managed to fix the problem. I repackaged the graphic files from Dragonfoot that Silverleaf recommended and added default.xml files to scale them correctly. As a result, a few things need to be done differently than in the tutorial. First of all, I'd suggest this background and line color rather than the color recommended by Silverleaf:
Then, instead of downloading the symbols as recommended, download this version:http://www.vintyri.org/downloads/blueclassic.zip
These are the same symbols as on the Dragonfoot site but packaged for FM8. I posted them on our website rather than on the NBOS site because the usage restrictions prohibit redistribution on commercial websites. The usage restrictions are in the download in the file license.txt.
After you've downloaded the zip file, unzip it into the FM8 folder MapArt (only there will it work right). With a default installation of FM8, the path starts in C:\Program Files or - if you're using Windows 7 or Vista 64-Bit - in C:\Program Files (x86). Here's the rest of the path:
The will create the folder Classic Blue Tiles and the subfolders Cavern Rooms and Dungeon Tiles, as shown above.
If you close and reopen FM8, you'll find the symbol set Classic Blue Tiles added with two categories. The first is called Cavern Rooms:
The second is called Dungeon Tiles:
Now ... when you work with Silverleaf's tutorial, follow his instructions until you reach Step 9, where he tells you to export your map. There's no longer any need to export. Simply stamp the symbols that you want on top of your map at the desired positions. The Dragonfoot graphics noiw work as normal FM8 raster symbols. One square in a symbol will scale to 10 by 10 feet, as recommended by Silverleaf.