Are you experiencing the "Error 0002 : Error has occurred, contact your webmaster. Incorrect data in 'blastchatc' table"? Here you can read what this error means and how to fix it.

Explanation:
BlastChat client, when loading chat, tries to identify your website URL in Joomla! and Mambo by using global variable $mosConfig_live_site. Using value of this variable, chat loads appropriate data from your database, _blastchatc table and sends them to blastchat server. If this fails, you get Error 0002.
Function bc_getLiveSite in file defaults.blastchatc.php is supposed to return correct URL of your website. So editing this function you can manipulate value of your website URL that BlastChat client "sees".

Joomla! 1.0.x and Mambo:
Variable $mosConfig_live_site is defined by default and you do not need to modify anything. But you are still getting error? Possible reasons and solutions on below.

Joomla! 1.5 legacy:
Joomla 1.5 in legacy mode is supposed to pre-fill deprecated variables like $mosConfig_live_site but it does not (we did not properly adjusted for this problem in client 2.3 release). Steps to fix it follows.

Joomla 1.0x and Mambo fix
Here are possible reasons: database read fails because data for your URL is not in _blastchatc table (table is corrupted, data is missing due deletion, you changed URL of your website in $mosConfig_live_site variable, etc).

If you did not manipulate your database, but you changed your website URL that was defined inside $mosConfig_live_site, simply go to admin backend and enter menu Components -> BlastChat client -> Registration which will attempt to create new data in _blastchatc table following with registration of your new URL.

If you manipulated your database (deleted, lost data, etc), you need to do same as previously, but most probably you will run into another error during registration, because URL is already registered. Read "How to re-register my website".

Joomla! 1.5 legacy fix
step 1:
Edit defaults.blastchatc.php (components/com_blastchatc directory).

step 2:
find and replace function bc_getLiveSite to (you have multiple options):

function bc_getLiveSite($ls) {

//this string must match your website URL that you registered with blastchat service!

return "http://www.yourdomain.com";

}

OR 

function bc_getLiveSite($ls) {

//this should return correct URL under Joomla 1.5

return substr_replace(JURI::root(), '', -1, 1);

}

OR

function bc_getLiveSite($ls) {

$request = & new JURI();

$mosConfig_live_site = $request->current();

if (!$mosConfig_live_site) {

$mosConfig_live_site = split("/index". $_SERVER["HTTP_HOST"] . $_SERVER["REQUEST_URI"]);

$mosConfig_live_site = $mosConfig_live_site[0];

}

}

In original function code we simply return value of parameter, which is $mosConfig_live_site variable supposed to be filled by CMS.

step 3:
admin backend menu Components - BlastChat client - Registration to create new data in _blastchatc table and/or to register new website and/or to confirm registration is valid

step 4
enter chat in frontend (if still error, delete your browser cache and try to enter chat again)