Attempted to create unknown entity type X

[Phloxicon]

I had my mod working perfectly but had to transfer it to a new computer. I keep getting this message:
Attempted to create unknown entity type my_entity_type
for each of my custom entities.

I changed the build path in Visual Studio. I can't recall what other paths I need to change. I moved the source files folder and the SourceMods mod folder. Can anyone tell me what I'm forgetting?

 

[Vegeta897]

Your name is fun to say.