I have a issue, When I try to select a message icon in the art tab of a weapon geck brings up a box looking for a nif file instead of a dds file.
Has anyone experienced this issue?

Yes, you are right, it seems like some kind of many bugs brought with FNV GECK version. You can correct it with FNVEdit adding correct path and file extension. After that edidting the small icon tab provides correct pathing and looking for proper extension.

Ahh yes I forgot about that nifty program...Thanks for the heads up Aurelinus.