I use XOOPS 2.0.9.2 and a big problem, y can not create new
custom block, y can see in preview,but when y push "submit" button i see reload the page but not "database updated succesfully" and the new custom block
don't appeare.

try upgrading to a newer version of xoops. I recommend the stable 2.0.13.1 version.

Upload the files, overwriting the current files, and update your system module.

Remember to backup your database first. (that way you can easily revert if needed)

It will be more secure and may solve the problem you're having with custom blocks.

D

Another option, update your system module for your version now admin>system>modules>system IT may do the trick.