Please use the proper URL. Although the site handles URLs case-insensitively, if you use wrong-case URLs, search engines will have to index each and every one of those URLs individually, which is a resource loss for both this site and the search engines. It also hinders caching.
Emulatordownloads/Fceu/Deprecated/Pcsx-rr-v0000003-src.7z may take you to the intended page if the site guessed your intents right.