strange widget behavior – cannot add directly

hi

i added to functions.php:

if (function_exists('register_sidebar')) {
	register_sidebar(array( 'name' => 'Str Glowna')) ;
}

i added to sidebar.php:

<?php if
   ( function_exists('dynamic_sidebar') && dynamic_sidebar('Str Glowna')) : else : ?>

	Prawy Sidebar

<?php endif; ?>

so everything is ok.

but when i go to wp-admin > widgets and i try to add widget it doesnt appear normally.

what i do:
1. go to widgets
2. drag some widget (for example Tags) to the right panel named ‘Str Glowna’
3. -> automatically close to button Save appears throbber (which normally eppears when you click save, but i didn’t click it yet)
4. i click save

what happen:
1. at website i dont see widget
2. when i refresh wp-admin > widgets widget is not in right panel but it is in bottom of page, in this section where lands all turned of widget.

so then i:
1. drag this widget from bottom of site to right panel
2. click save (throbber shows for moment)
3. -> now everything works OK

can anyone tell me why it behaves like that? i use 2.8.5 but at other servers i have ssamme version and there everything is ok