"Undefined index: #rows in weight_node_admin()" and "Invalid argument supplied for foreach() in weight_node_admin()"

After updating the module, I'm getting these notices:

Notice: Undefined index: #rows in weight_node_admin() (line 154 of /var/www/vhosts/domain.com/subdomains/preview/httpdocs/sites/all/modules/weight/weight.module).
    Warning: Invalid argument supplied for foreach() in weight_node_admin() (line 154 of /var/www/vhosts/domain.com/subdomains/preview/httpdocs/sites/all/modules/weight/weight.module).

When viewing the content overview (admin/content) I was getting these notices as well (about 50 of them under each other):

Notice: Undefined index: weight in theme_tableselect() (line 3210 of /var/www/vhosts/domain.com/subdomains/preview/httpdocs/includes/form.inc).
    Notice: Undefined index: weight in theme_tableselect() (line 3210 of /var/www/vhosts/domain.com/subdomains/preview/httpdocs/includes/form.inc).
    Notice: Undefined index: weight in theme_tableselect() (line 3210 of /var/www/vhosts/domain.com/subdomains/preview/httpdocs/includes/form.inc).

Also: the capabalitity to assign a weight in the overview is gone. The column is still there, but it's empty.

All this happened after the update. Right after enabling the module I've run an update.php which told me there was one update (7207 - Remove unneeded weight field).

After the errors occured I disabled the module again, uninstalled it, re-enabled it, ran update.php ("no updates"), but all the mentioned errors are still there.

What's the best I can do at the moment?