Hai..i have a problem here...
i use XOOPS 2.1
when installing this pakcage on my server hosting there is no error message, but after i log in as webmaster to go to main page (after instalation process) there are many error message in the bottom of my main page, for example below :

Notice [PHP]: Only variable references should be returned by reference in file include/functions.php line 566
Notice [PHP]: Only variable references should be returned by reference in file include/functions.php line 566
Notice [PHP]: Only variable references should be returned by reference in file include/functions.php line 566
Notice [PHP]: Only variable references should be returned by reference in file include/functions.php line 566
Notice [PHP]: Only variable references should be returned by reference in file include/functions.php line 566
Notice [PHP]: Only variable references should be returned by reference in file kernel/user.php line 609
Notice [PHP]: Only variable references should be returned by reference in file include/functions.php line 566
Notice [PHP]: Only variable references should be returned by reference in file kernel/object.php line 803
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 108
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 108
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file kernel/configitem.php line 97
Notice [PHP]: Only variable references should be returned by reference in file include/functions.php line 566
Notice [PHP]: Only variable references should be returned by reference in file include/functions.php line 566
Notice [PHP]: Only variable references should be returned by reference in file kernel/object.php line 803
Notice [PHP]: Only variable references should be returned by reference in file class/module.textsani..
..
..
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why this can happen ??
please help me..

I believe these messages are erroneous, and you can disregard them.

Sounds like you've got debugging on, which should be able to be turned off in the system admin / preferences area.

Try turning off phpdebug in admin preferences area, assuming you're not actually having problems with the site and are only annoyed by the messages.

If you are having site problems... I recommend using the recommended version of Xoops- 2.0.13.2 (it is MUCH more stable and less prone to problems).

When starting out lots of things can happen to confuse us. using FAQ is a great way to understand things. Also there are the supprt docs in the get help docs here thread below.

Hope these help!