I just installed XOOPS 2.2.3 and I get the following errors

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 kernel/profile.php line 94
Notice [PHP]: Only variables should be assigned by reference in file modules/profile/include/forms.php line 265
Notice [PHP]: Only variables should be assigned by reference in file modules/profile/include/forms.php line 272
Notice [PHP]: Only variables should be assigned by reference in file modules/profile/include/forms.php line 280
Notice [PHP]: Only variables should be assigned by reference in file modules/profile/register.php line 223

These are notices and nothing more, you have no need to worry about them.

The newest version of PHP seems to have changed and hence the reason you are now getting these. :)

They show up on my frontpage, on the bottom, and on every other page as well.

I want to get rid of them, I cannot change anything to php, cuz my host is in control of that.

Just turn off php debug through the admin section of your XOOPS site, system preferences.