Joomla SEO friendly links problem - Joomla! Forum - community, help and support

when change htaccess.txt .htaccess , turn on "search engine friendly urls:" links break. can me?
i using .htaccess in joomla install.


listed below.
thank you
-b



##
# @version $id: htaccess.txt 5973 2006-12-11 01:26:33z robs $
# @package joomla
# @copyright copyright (c) 2005 open source matters. rights reserved.
# @license http://www.gnu.org/copyleft/gpl.html gnu/gpl
# joomla! free software
##


#####################################################
#  read if choose use file
#
# line below section: 'options +followsymlinks' may cause problems
# server configurations.  required use of mod_rewrite, may already
# set server administrator in way dissallows changing in
# .htaccess file.  if using causes server error out, comment out (add # to
# beginning of line), reload site in browser , test sef url's.  if work,
# has been set server administrator , not need set here.
#
# use 1 of 2 sef sections follow.  lines can uncommented
# (and used) have 1 #.  lines 2 #'s should not uncommented
# in section don't use, lines should start #
#
# standard sef, use standard sef section.  can comment out
# of rewritecond lines , reduce server's load if you
# don't have directories in root named 'component' or 'content'
#
# if using 3rd party sef or core sef solution
# uncomment of lines in '3rd party or core sef' section
#
#####################################################

#####  solving problems component url's don't work #####
# special note smf users when smf integrated , bridged
# or situation component's url's aren't working
#
# in both 'standard sef', , '3rd party or core sef' sections line:
# rewritecond %{request_uri} ^(/component/option,com) [nc,or] ##optional - see notes##
# may need uncommented.  if running joomla!/mambo from
# subdirectory name of subdirectory need inserted this
# line.  example, if joomla!/mambo in subdirectory called '/test/',
# change this:
# rewritecond %{request_uri} ^(/component/option,com) [nc,or] ##optional - see notes##
# this:
# rewritecond %{request_uri} ^(/test/component/option,com) [nc,or] ##optional - see notes##
#
#####################################################


##  can commented out if causes errors, see notes above.
options +followsymlinks

#
#  mod_rewrite in use

rewriteengine on


#  uncomment following line if webserver's url
#  not directly related physical file paths.
#  update joomla!/mambodirectory (just / root)

# rewritebase /


########## begin - joomla! core sef section
############# use section if using joomla! core sef
## (rewritecond) lines in section required if actually
## have directories named 'content' or 'component' on server
## if not have directories these names, comment them out.
#
rewritecond %{request_filename} !-f
rewritecond %{request_filename} !-d
#rewritecond %{request_uri} ^(/component/option,com) [nc,or] ##optional - see notes##
rewritecond %{request_uri} (/|\.htm|\.php|\.html|/[^.]*)$  [nc]
rewriterule ^(content/|component/) index.php
#
########## end - joomla! core sef section



########## begin - 3rd party sef section
############# use section if using 3rd party (non joomla! core) sef extension - e.g. opensef, 404_sef, 404sefx, sef advance, etc
#
#rewritecond %{request_uri} ^(/component/option,com) [nc,or] ##optional - see notes##
#rewritecond %{request_uri} (/|\.htm|\.php|\.html|/[^.]*)$  [nc]
#rewritecond %{request_filename} !-f
#rewritecond %{request_filename} !-d
#rewriterule (.*) index.php
#
########## end - 3rd party sef section



########## begin - rewrite rules block out common exploits
## if experience problems on site block out operations listed below
## attempts block common type of exploit `attempts` joomla!
#
# block out script trying set mosconfig value through url
rewritecond %{query_string} mosconfig_[a-za-z_]{1,21}(=|\%3d) [or]
# block out script trying base64_encode crap send via url
rewritecond %{query_string} base64_encode.*\(.*\) [or]
# block out script includes