step7 300 scl source code

Hello all, I have a fc block that is in SCL from one proj that I would like to put in another. I've read about the source code file wich I can get from the proj. But I can't figer out what to do with it. when I copy it into the source folder and then try to compil I get this ERROR "symbolic block name: 'FC_DWORD_TEST' not recognized. I've already added the fc block into the block folder.
any help would be great thanks.

Replace 'FC_DWORD_TEST' with FCxx where xx is the number of the FC.