Important Error: mb_substr() expects parameter 3 to be long, string given in /home/mydomain/public_html/libraries/phputf8/mbstring/core.php on line 88

No it's not hosted locally - it's hosted with Rochen. As I said in my first post this error only appeared recently.

I'm sorry but, because it would appear that you don't want us to see your website - where you are having your problem - I can only conclude that this is something you will need to discuss further with your webhosting provider. In your case that is Rochen. Otherwise, you could look at the following search results from Google to see if they shed some light on the matter: >>> here <<<

I'm happy to PM you the link to the site, that is if you are happy for me to do so.

I would be happier if you posted your unedited Kunena configuration report here. I may not be the person who has the technical knowledge to help you. I don't know everything; there are many other members of the Kunena team who may have a better insight into these issues and you may need to be patient for their input. The more information you can give (and your unedited configuration report will provide that information) the better.

Please read again, very carefully, What information should I include when I ask for help (including how to post my configuration report)? You will see that the only people who can read certain parts of the report are the administrators of www.kunena.org , the moderators of this forum and you. No-one else can read those things.

Here's the unedited config report.

Thanks in advance

Database collation check: The collation of your table fields are correct

Legacy mode: Disabled | Joomla! SEF: Disabled | Joomla! SEF rewrite: Disabled | FTP layer: Disabled |

This message contains confidential information

htaccess: Exists | PHP environment: Max execution time: 30 seconds | Max execution memory: 128M | Max file upload: 20M

Kunena menu details:

Joomla default template details : ablePixel06 | author: Q.Lotts | version: 1.1.0 | creationdate: Jan 2011

Kunena default template details : Blue Eagle (default) | author: Kunena Team | version: 1.7.2 | creationdate: 2012-01-31

Kunena version detailled: Installed version: 1.7.2 | Build: 5215 | Version name: Omega | Kunena detailled configuration:

Warning: Spoiler!

[th]Kunena config settings:[/th]

board_offline	0
board_ofset	0
enablerss	1
enablepdf	1
threads_per_page	20
messages_per_page	6
messages_per_page_search	15
showhistory	1
historylimit	6
shownew	1
jmambot	0
disemoticons	0
template	default
showannouncement	1
avataroncat	0
catimagepath	category_images/
showchildcaticon	1
annmodid	62
rtewidth	450
rteheight	300
enableforumjump	1
reportmsg	1
username	1
askemail	1
showemail	0
showuserstats	1
showkarma	1
useredit	1
useredittime	0
useredittimegrace	600
editmarkup	1
allowsubscriptions	1
subscriptionschecked	1
allowfavorites	1
maxsubject	50
maxsig	300
regonly	0
changename	0
pubwrite	0
floodprotection	0
mailmod	1
mailadmin	0
captcha	1
mailfull	1
allowavatar	1
allowavatarupload	1
allowavatargallery	1
avatarquality	65
avatarsize	2048
allowimageupload	0
allowimageregupload	1
imageheight	800
imagewidth	800
imagesize	150
allowfileupload	0
allowfileregupload	1
filetypes	zip,txt,doc,gz,tgz,jpg,gif,png,pdf
filesize	120
showranking	1
rankimages	1
avatar_src
fb_profile
pm_component
userlist_rows	30
userlist_online	1
userlist_avatar	1
userlist_name	1
userlist_username	1
userlist_posts	1
userlist_karma	1
userlist_email	0
userlist_usertype	0
userlist_joindate	1
userlist_lastvisitdate	1
userlist_userhits	1
latestcategory	0
showstats	0
showwhoisonline	1
showgenstats	0
showpopuserstats	1
popusercount	5
showpopsubjectstats	1
popsubjectcount	5
usernamechange	0
rules_infb	1
rules_cid	304
help_infb	1
help_cid	305
showspoilertag	1
showvideotag	1
showebaytag	1
trimlongurls	1
trimlongurlsfront	40
trimlongurlsback	20
autoembedyoutube	1
autoembedebay	1
ebaylanguagecode	en-us
fbsessiontimeout	1800
highlightcode	0
rss_type	topic
rss_timelimit	month
rss_limit	100
rss_included_categories
rss_excluded_categories
rss_specification	rss2.0
rss_allow_html	1
rss_author_format	name
rss_author_in_title	1
rss_word_count	0
rss_old_titles	1
rss_cache	900
fbdefaultpage	categories
default_sort	asc
alphauserpointsnumchars	0
sef	1
sefcats	0
sefutf8	0
showimgforguest	1
showfileforguest	1
pollnboptions	4
pollallowvoteone	1
pollenabled	1
poppollscount	5
showpoppollstats	1
polltimebtvotes	00:15:00
pollnbvotesbyuser	100
pollresultsuserslist	1
maxpersotext	50
ordering_system	mesid
post_dateformat	ago
post_dateformat_hover	datetime
hide_ip	1
js_actstr_integration	0
imagetypes	jpg,jpeg,gif,png
checkmimetypes	1
imagemimetypes	image/jpeg,image/jpg,image/gif,image/png
imagequality	50
thumbheight	32
thumbwidth	32
hideuserprofileinfo	put_empty
integration_access	communitybuilder
integration_login	communitybuilder
integration_avatar	communitybuilder
integration_profile	communitybuilder
integration_private	none
integration_activity	communitybuilder
boxghostmessage	0
userdeletetmessage	0
latestcategory_in	1
topicicons	1
onlineusers	1
debug	0
catsautosubscribed	0
showbannedreason	0
version_check	1
showthankyou	1
showpopthankyoustats	1
popthankscount	5
mod_see_deleted	0
bbcode_img_secure	text
listcat_show_moderators	1
lightbox	1
activity_limit	0
show_list_time	720
show_session_type	0
show_session_starttime	0
userlist_allowed	0
userlist_count_users	1
enable_threaded_layouts	0
category_subscriptions	post
topic_subscriptions	every
pubprofile	1
thankyou_max	10
email_recipient_count	0
email_recipient_privacy	bcc
email_visible_address
captcha_post_limit	0

Third-party components: CommunityBuilder 1.7.1

Third-party SEF components: sh404sef: The file doesn't exist sh404sef.xml !

Plugins: System - Mootools Upgrade: Disabled | System - Mootools12: Disabled

Modules: Kunena Latest 1.7.2 | Kunena Login 1.7.2

Looks like mb_substr() provided by Joomla isn't fully compatible with the real one. You get this error only if PHP hsan't been built with multibyte support turned on, or the extension has been disabled in PHP.

For performance reasons I advice to turn it on.