You are likely missing part01.rar or part02.rar . The extraction must start from the first file.
Select or "Extract to RRRDDD/" using software like WinRAR , 7-Zip , or The Unarchiver (for Mac). RRRDDD.part03.rar
The software will automatically pull data from part03.rar and the others to create the final file. Troubleshooting You are likely missing part01