Was trying to change the the weight of blocks inside the admin panel. After pressing save I get an error. This error is reproducible on all of my 3 forums. This one is from my test forum.

But even with the error the weight changed correct on the frontpage.

array(8) { ["test_post"]=> string(18) "!AwCT43Vhl#$@kDbkF" ["bid_1"]=> string(15) "block_main_menu" ["bweight_1"]=> string(1) "2" ["bid_2"]=> string(18) "block_footer_right" ["bweight_2"]=> string(1) "0" ["bid_3"]=> string(15) "block_main_menu" ["bweight_3"]=> string(1) "1" ["CSRF_token"]=> string(32) "a022c18a135c76e06c50f547f0d54aa4" } 
Notice: Undefined index: bweight_test_post in /home/www/new/forum/admin/modules/ui/blocks.php on line 111

Notice: Undefined index: bweight_bweight_1 in /home/www/new/forum/admin/modules/ui/blocks.php on line 111

Notice: Undefined index: bweight_bweight_2 in /home/www/new/forum/admin/modules/ui/blocks.php on line 111

Notice: Undefined index: bweight_bweight_3 in /home/www/new/forum/admin/modules/ui/blocks.php on line 111

Notice: Undefined index: bweight_CSRF_token in /home/www/new/forum/admin/modules/ui/blocks.php on line 111

Warning: Cannot modify header information - headers already sent by (output started at /home/www/new/forum/admin/modules/ui/blocks.php:105) in /home/www/new/forum/admin/modules/ui/blocks.php on line 122

We are not able to reproduce this problem.

Which version of codoforum are you using ?

3.4 Beta from you site:
https://codoforum.com/

Thats strange, can you try deleting the blocks and create them again.

Yes I can delete them, no error. I can add blocks no matter which region I choose with or without content. After pressing save, even if I not changed the weight so all block are on 0 the error comes back.