Just FYI, I've since tried to get Dash Faction to work and had nothing but problems. It wouldn't let me select my mod in the launcher menu (not sure why). It worked fine with Pure Faction.
Ultimately though, I couldn't even get Dash Faction to run at all. It kept telling me I had the wrong version of rf.exe. I have it on disc and applied the official patches, so not sure why it's complaining.
Dash Faction support is provided by the community & the developer at the Red Faction community Discord: http:// redfaction.chat - please join and we'll get you up and running ;)
That being said, if you have the disc version and apply the official patches, it should work - that's the version it requires. If you're using the GoG or Steam version, there's an additional step required - though the new version of Dash (due out in the very near future) will automatically handle all of that for you.
As for not allowing you to select your mod, I expect this is also related to the .exe issue you're having. Please join the RF community Discord (http:// redfaction.chat) and we will get this all fixed up for you :)
PS. Also, be sure to follow the installation instructions for Dash Faction (available in the quick start guide on http:// redfaction.help) - they will will walk you through getting the correct version of rf.exe.