7
finaly I solved the problem, the only thing I needed to do was to reinstall xoops, I am realy happy, I did not have to reinstall xp or internet :) The problem seems to be connected with corrupted theme.
still just after reinstallation of XOOPS and article, when I have updated article the following error messages occured -
Notice: Undefined variable: sql in file /modules/article/include/functions.php(132) : eval()'d code line 748
Notice: Undefined variable: sql in file /modules/article/include/functions.php(132) : eval()'d code line 749
so it seems that there is something wrong with the source