This error occurs when attempting to run any command:
Packed file is corrupt
The zip files in the %ARC%/PROGRAMS are corrupt. You can test this by manually unzipping the zip files in the PROGRAMS subdirectory. For example:
Make sure you have the correct version of PKUNZIP (2.04g) on your system. To check this, type:
If the files fail to unzip, you may have a conflict with the memory manager. One symptom is the DOS Utility Commands (PLOT, W, L, DOS2UNIX) only work when ARC is started. Normally, they should also work from DOS. Some versions of Quarter Deck's QEMM have been known to cause problems. Try replacing the QEMM line in the config.sys with the DOS expanded memory manager EMM386.
If this still doesn't resolve the error, you need to reinstall PC ARC/INFO.