Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

You may be attempting to do one of the following:
  ■ Use a feature of another version of BASIC that
    is not available with Microsoft BASIC.
  ■ Perform an ISAM operation without the correct
    ISAM TSR loaded (PROISAM or PROISAMD).
  ■ Use a feature of Microsoft BASIC that is unavailable
    under the operating system you are running. Such as:
      ■ Using the LOCK or UNLOCK statement while running
        DOS 2.1.
      ■ Using the SHELL function while running DOS
        instead of OS/2.
      ■ Using the PALETTE or PCOPY statement while
        running OS/2.
 
ERR code: 73