You need to make sure that the compiler can find the header (and source) files. If you add a new folder, you need to tell this the compiler.
You can find the settings in
Project > Properties > C/C++ Build > Settings > ColdFire Compiler > Input
resp.
Project > Properties > C/C++ Build > Settings > HCS08 Compiler Input
There you find settings for include file path (both system and user includes).
Hope that helps,
BK