The 2009 original remains a benchmark for the franchise, though its modern experience varies by platform:

The file code_pre_gfx_mp.ff is a critical "FastFile" (.ff) asset used by Call of Duty: Modern Warfare 2

As a last resort, you might need to reinstall Modern Warfare 2. This can help replace any missing or corrupted files, including "code-pre-gfx-mp.ff."