)
Call error retrieval function with:
	AX = error number (see #02616)
	DI = offset of error table
Return: ES:DI -> error message (counted string)
Notes:	this function needs to access COMMAND.COM if the messages were not
	  loaded into memory permanently with /MSG; the caller should assume
	  that the returned message will be overwritten by the next call of
	  the function
	supported by DR DOS 5.0