Problem on Installation

Dear Sir,

I tried to install PostgreSQL 8.1.15 on Freebsd 7.0. When I extracted
the .tar.gz and inputed 'make' it shows the following error:

"/usr/share/mk/bsd.port.mk", line 11: Could not find
/usr/ports/Mk/bsd.port.mk
"Makefile", line 177: Malformed conditional (${ARCH} == sparc64 &&
${OSVERSION} < 700000)
"Makefile", line 179: if-less endif

Please help, and thanks in advance.