nvnet port build problem

[Bozhidar Batsov]

This might be helpful - the contents of my Makefile:
# Ports collection makefile for: nvnet
#
# Date created: 1 Oct 2003
# Whom:         Quinton Dolan <q at onthenet.com.au>
#
# $FreeBSD: ports/net/nvnet/Makefile,v 1.3 2004/12/14 15:56:04 ru Exp $
#

PORTNAME=       nvnet
PORTVERSION=    1.0.${NVVERSION}
PORTREVISION?=  0
CATEGORIES=     net
                http://www.onthenet.com.au/~q/nvnet/:nvnet
DISTFILES=      NVIDIA_nforce-1.0-${NVVERSION}${EXTRACT_SUFX}:nvidia \
                nvnet-src-${NVNETVERSION}${EXTRACT_SUFX}:nvnet

MAINTAINER=     q at onthenet.com.au
COMMENT=        Driver for NVIDIA MCP Ethernet adapter

NVNETVERSION=   20040813

NO_PACKAGE=     Depends on kernel
ONLY_FOR_ARCHS= amd64 i386
MD5_FILE=       ${MASTERDIR}/distinfo.${ARCH}
WRKSRC=         ${WRKDIR}/nvnet
MODULES_WITH_WORLD=
PLIST_SUB=      KMODDIR=${KMODDIR}
PORTDOCS=       README nvidia_pci.c.diff
MAN4=           nvnet.4

.include <bsd.port.pre.mk>

.if ${OSVERSION} < 480100 || ${OSVERSION} >= 500000 && ${OSVERSION} <
501000
BROKEN=         "Systems prior to FreeBSD 4.9 & 5.1 are not supported"
.endif

.if ${ARCH} == "i386"
NVVERSION=      0274
.elif ${ARCH} == "amd64"
NVVERSION=      0275
.else
NVVERSION=      0
.endif

pre-fetch:
.if !exists(${SRC_BASE}/sys/Makefile)
        @${ECHO} "*************************************************"; \
        ${ECHO}  "This port requires the kernel source be available"; \
        ${ECHO}  "*************************************************"; \
        exit 1
.endif

do-install:
        ${INSTALL_SCRIPT} ${WRKSRC}/module/if_nv.ko ${KMODDIR}
        ${INSTALL_MAN} ${WRKSRC}/man/nvnet.4 ${PREFIX}/man/man4
.if !defined(NOPORTDOCS)
        ${MKDIR} ${DOCSDIR}
.for i in ${PORTDOCS}
        ${INSTALL_MAN} ${WRKSRC}/doc/${i} ${DOCSDIR}
.endfor
.endif
        @${CAT} ${PKGMESSAGE}

.include <bsd.port.post.mk>