Running from eclipse when using an api gives "Duplicate mod sources"

[naturaGodhead]

I use another mod as an api to make an addon for that mod. I have an issue where I'm trying to run from inside eclipse, and I get "You have mod sources that are duplicate within your system." There is only one copy of the jar located in run/mods, and my build path is pointed at that jar. I've tried moving the jar outside of run/mods to libs/ instead, and also trying to have jars in both places with the build path pointed at libs/, and still get the same issue.  If I remove the jar from run/mods completely and only have the one in libs/ with the build path pointed at it, the game crashes because the dependency is not in the mods folder. If it's there, it sees 2 jars, but if it isn't it sees 0. Anyone have a similar issue?

[MDW01]

Post your code. Do the mods have the same file name or mod ID?