[31] pkunzip reports a CRC error!

The portable zip 1.1 contains many workarounds for undocumented restrictions
in pkunzip. Compatibility is ensured for pkunzip 1.10 only. All previous
versions (pkunzip 1.0x) have too many bugs and cannot be supported. This
includes Borland unzip.

So if your pkunzip reports a CRC error, check that you are not using
an obsolete version. Get either pkzip 2.04g or unzip 5.12 (see question
2 above for ftp sites). To generate zip files compatible with pkunzip 1.10,
use zip 1.1 (see item 2 above for ftp site).