@san37
Lol, do you pay them?
Error 404 means problem with server on particular URL and they told you there is different CSS file?
Do not ask us for help with your hosting. You paid us for theme, you paid your hosting provider for hosting, so they are paid to support you... but as you can see, they do not have any knowledge.

Yes they are and write what they don't know what is the reason they are not programmers, of course paid hosting but they do not understand at all 

The thing is that even if you set another template of the standard revealed this error
You as a professional can recommend how to fix it and what to look for?

@san37
I am pretty sure it is caused by incompatibility in URLs, you should first try it with friendly URLs off.
After that you can try to identify which part of code cause it. This page consist of files:
- head.php
- header.php
- inc.search.php
- inc.category.php
- search.php
- search_gallery.php
- footer.php

Backup first, then remove content of each to see if you still got error 404.

I remember that on elena theme was code that blocked search page to error 404 page when friendly URLs were activated due to following code:
if(Params::getParam('sCategory') == 0) {
  Params::unsetParam('sCategory');
}

You may find something similar...

Yes you are right, disable friendly url and everything works well...

Please specify which files can be code

if(Params::getParam('sCategory') == 0) {
Params::unsetParam('sCategory');
}

@san37
It was example, it is not present in zara theme, just letting you know how could problematic code look.

I think to solve this problem Infinite scrol
You don't have such a plugin?

@san37
No, but it was somewhere on forums.

found http://forums.osclass.org/themes/infinite-scroll-items/

1 and 2 step completed

But not working yet
look, I correctly pointed classes?
This code I placed in search.php

<script type="text/javascript">
jQuery.ias({
container : '.search-items',
item: '.list-prod',
pagination: '.paginate',
next: '.searchPaginationNext',
loader: '<?php echo osc_current_web_theme_url('images/loader.gif'); ?>'
loaderDelay: 100,
triggerPageTreshold: 3,
trigger: 'More items',
tresholdMargin: 0,
history : true
});
</script>
code appears at the very end before </body>

<script type="text/javascript" src="<?php echo osc_current_web_theme_js_url('jquery.ias.min.js') ; ?>"></script>
specified before </head > in search.php

@san37
Never tested this plugin, you may need to change classes in your script.

I put classes that I wanted you to look right if I indicated

jQuery.ias({
                  container : '.search-items',
                  item: '.list-prod',
                  pagination: '#main .paginate',
                  next: '.searchPaginationNext',
                  loader: '<?php echo osc_current_web_theme_url('images/loader.gif'); ?>'
                  loaderDelay: 100,
                  triggerPageTreshold: 3,
                  trigger: 'More items',
                  tresholdMargin: 0,
                  history : true
               });

Also not working

@san37
That is probably for different discussion, you should reach plugin author.

Thanks, the problem was solved