Be cautious when opening compressed files from unknown sources. It is highly recommended to before extracting, as .rar archives are a common way to distribute malware disguised as software updates.
Because this is a "Part 08" file, it cannot be opened or extracted on its own. You will need all the other parts (Part 01 through Part 07, and any subsequent parts) saved in the same folder to successfully access the content. Likely Contents ER40V.part08.rar