I found it and it does appear twice but... now what? I'll be perfectly honest, I have no idea what I'm doing and I'd rather not break anything.
EDIT: never mind, I figured it out. If anyone is as big a noob at this as me is reading this, Once you find the log file (which in its self is a bit of an adventure) find the DLL using the Edit>find function in notepad, then copy-paste the path into your file explorer. Once there, just delete the duplicate mod. For me, this mod was included in another mod without me noticing, so it was causing things to break. Now that I've uninstalled the one that came bundled with it (in this case Airplanes Plus) everything is working fine.