Download them all: ERAS2.6.7z.001 through ERAS2.6.7z.012.
Make an empty folder for the game (Example C:\ERAS2) Right click ERAS2.6.7z.001, choose 7-zip/Open archive and from there, extract to C:\ERAS2). You should see in the archive, upon opening with 7-zip, modules folder, Program folder, RESOURCE folder, fmod.dll, start.exe, config.exe Buccaneer’s Reef file, start.ini, etc. Copy them all.
Unzip Update.zip and overwrite everything in that to C:\ERAS2.
Unzip EngineUpdate.zip and overwrite everything in that to C:\ERAS2