I'm not familiar with that particular font, but did a Google search and came up with this - is that the correct font? the reason I ask is I don't see a double line around this particular font so wanted to double check.
After you created the tool path, did you delete the original design prior to exporting it as a DXF? If not, that might be the source of your double lines. (Did the oval around the sign cut double also, or just the letters?)