Installed but XOOPS show this

Notice [PHP]: Only variables should be assigned by reference in file include/common.php line 215
Notice [PHP]: Only variables should be assigned by reference in file kernel/config.php line 239
Notice [PHP]: Only variables should be assigned by reference in file kernel/config.php line 239
Notice [PHP]: Only variables should be assigned by reference in file kernel/groupperm.php line 229
Notice [PHP]: Only variables should be assigned by reference in file kernel/blockinstance.php line 169
Notice [PHP]: Only variable references should be returned by reference in file kernel/blockinstance.php line 111
Notice [PHP]: Only variables should be assigned by reference in file modules/system/blocks/system_blocks.php line 151
Notice [PHP]: Only variables should be assigned by reference in file kernel/groupperm.php line 229
Notice [PHP]: Only variables should be assigned by reference in file modules/system/blocks/system_blocks.php line 154
Notice [PHP]: Only variables should be assigned by reference in file modules/system/blocks/system_blocks.php line 159
Notice [PHP]: Only variables should be assigned by reference in file modules/system/blocks/system_blocks.php line 159
Notice [PHP]: Only variables should be assigned by reference in file modules/system/blocks/system_blocks.php line 159

Pls teach me.

This is just the PHP debug messages. They're only Notices so nothing to worry about. Go into System Admin -> Preferences -> General Settings and change the Debug Mode to Off from PHP Debug. Now you shouldn't see any messages.

Thank you so much. Now I very enjoy with XOOPs.