CRC error when extracting BIN files

[BMWZ3]

I hope someone can help me here.

After downloading all the parts to a RAR file. I try to extract the BIN and it gives me the error "CRC error unable to extract" . But I still see it created a BIN file.

Does that mean the BIN file is bad ? If so, does that mean I have to redownload ALL parts of the RAR or can I find out which part of the RAR is bad ??

Thanks in Advance !!