There are two types of adjustments to make. The first concerns the number
of file handless available.

Use your editor (QEDIT, BRIEF or whatever) to edit config.sys.
It must contain a line like

        files=65 (you can make the number higher, but keep it odd),

and a line like

        shell=c:\command.com /P /E:2048

(This is DOS 3.3 syntax; see the DOS manual for other versions). In
general, you should make the "E" setting 1k (1048 bytes) higher than it
had been.