$bbfile="c:\\webserver\\osarr.org\\www\\member\\bboard\\bb.html";
$tempfile="c:\\webserver\\osarr.org\\www\\member\\bboard\\bb.html";
[...]
rename("$bbfile", "$bbfile.old");
rename("$tempfile", "$bbfile");

##</code><code>##

$tempfile="c:\\webserver\\osarr.org\\www\\member\\bboard\\bb.html.tmp";

##</code><code>##

open(TEMPFILE,">$tempfile") || die("Can't open $tempfile: $!");

##</code><code>##

c:\webserver\
c:\webserver\osarr.org\
c:\webserver\osarr.org\www\
c:\webserver\osarr.org\www\member\
c:\webserver\osarr.org\www\member\bboard\

##</code><code>##

open(TEMPFILE, "$tempfile") || die("Can't open $tmpfile: $!");