Are you getting a (like "CRC failed" or "Can't open file")? Do you have all the other parts of the archive? What is the total size of the files you currently have?

If you downloaded this from an untrusted source, run a virus scan before opening any extracted files. Large split archives are sometimes used to hide malware from simple web scanners. If you're having trouble, let me know:

If you are missing any numbered file in the sequence, the extraction will fail with a "Data error" or "Unexpected end of archive."