Site->Multisite: error slug category

Hi, I solve the problem:

I had wordpress installed and everything worked.
I recently decided to change the installation miltisites, again everything works fine.

I just have a problem with the URL. For categories I had set slug “styl”, so that URL looks like:

http://www.metalsvet.cz/styl/death-metal/

After activation multisites is now URL (events/categories/…):

http://metalsvet.cz/events/categories/death-metal

🙁 I do not want this URL

Other slug working properly, the problem is only with the categories.
Can anyone advise me? Slug I still set to “styl”

http://ww.wp.xz.cn/extend/plugins/events-manager/