A lot of people tend to have an error when adding in new scripts that is something along the lines of:
CLIENTFIELD MISMATCH ERROR.
The reason as to why this happens is because you have a #using somewhere in your mapname.gsc that is not called in your mapname.csc or vice versa.
Before running your map, while in Launcher, underneath RUN you can see a grey box that you can input custom DVARS. Paste the following into that box:
+set com_clientfieldsdebug 1 +set logfile 1
Now run your map. After you get your error, press SHIFT + ~ to bring up the console along with the consoles history. Scroll up and eventually it will reveal which #usings are missing in either your mapname.gsc or mapname.csc.