You are working on script mods for Left 4 Dead 2 and when you are loading your mod, you keep getting an error about a missing open curly brace. You've checked the file and everything appears to be lining up.
Valve does a lot of things right with the Source engine. Handling byte-order markers at the beginning of scripts is not one of them. Open a command prompt, browse to your script, and use the "more" command to output your script to the command line. What you are looking for is three garbage characters at the beginning of your script.
If you see those garbage bytes, congratulations, you've got an easy problem to solve.
Download and install Notepad++. Open your script. Go to the Encoding menu. Change the encoding to either "Encode in ANSI" or "Encode in UTF-8 without BOM." Save your script.