The installation process for the FLAC plugin in Nero 7 is manual but straightforward. The critical factor is placing the DLL files in the correct directory. Note that the installation path is different for Nero 7 compared to later versions like Nero 8 or 9, and mixing them up is the most common cause of the plugin not working.
What (e.g., Windows 10, Windows XP) are you running Nero 7 on? flac plugin nero 7 full