Hmm, strange. Now links are ok, maybe it something related to cache.
BTW, if forum located in some folder, that contain letter "f" in it's name, rules in .htaccess won't work. Why not to correct them like that:
PHP Code:
RewriteEngine On
RewriteRule ^(.*)t([0-9]+)(.*)newpost(.*)$ showthread.php?t=$2&goto=newpost [QSA,L]
RewriteRule ^(.*)\-f(.*)/(.*)t([0-9]+)(.*)/post([0-9]+)(.*)$ showpost.php?p=$6 [QSA,L]
RewriteRule ^(.*)\-f(.*)/(.*)t([0-9]+)(.*)/([a-z]+)([0-9]+)(.*)$ showthread.php?t=$4&page=$7 [QSA,L]
RewriteRule ^(.*)\-f(.*)/(.*)t([0-9]+)(.*)$ showthread.php?t=$4 [QSA,L]
RewriteRule ^(.*)\-f([0-9]+)/([a-z]+)([0-9]+)(.*)$ forumdisplay.php?f=$2&page=$4 [QSA,L]
RewriteRule ^\-f([0-9]+)(.*)$ forumdisplay.php?f=$1 [QSA,L]
RewriteRule ^(.*)\-f([0-9]+)(.*)$ forumdisplay.php?f=$2 [QSA,L]