    void re_yy_switch_to_buffer  (YY_BUFFER_STATE  new_buffer , yyscan_t yyscanner)
{
    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;

	/* TODO. We should be able to replace this entire function body
	 * with
	 *		re_yypop_buffer_state();
	 *		re_yypush_buffer_state(new_buffer);
     */
	re_yyensure_buffer_stack (yyscanner);
	if ( YY_CURRENT_BUFFER == new_buffer )
		return;

	if ( YY_CURRENT_BUFFER )
		{
		/* Flush out information for old buffer. */
		*yyg->yy_c_buf_p = yyg->yy_hold_char;
		YY_CURRENT_BUFFER_LVALUE->yy_buf_pos = yyg->yy_c_buf_p;
		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = yyg->yy_n_chars;
		}

	YY_CURRENT_BUFFER_LVALUE = new_buffer;
	re_yy_load_buffer_state(yyscanner );

	/* We don't actually know whether we did this switch during
	 * EOF (re_yywrap()) processing, but the only time this flag
	 * is looked at is after re_yywrap() is called, so it's safe
	 * to go ahead and always set it.
	 */
	yyg->yy_did_buffer_switch_on_eof = 1;
}

The product dereferences a pointer that it expects to be valid but is NULL.