If errors occur when saving product attributes in Modified Shop (xtcmodified) after the online shop creation, this may be related to the number of attributes if the so-called Suhosin component is installed on the underlying server.
This security component limits, among other things, the number of variables in POST, GET, and REQUEST processes. If these limits are set too low, attributes exceeding the defined limit will not be saved. The problem can be resolved by adjusting the relevant settings in suhosin.ini and restarting the server (if you do not have access to suhosin.ini, simply contact your hosting provider or, if possible, set the settings via .htaccess), for example:
suhosin.request.max_vars = 0
suhosin.post.max_vars = 0
suhosin.get.max_vars = 0
