Permalink structure /blog/Êtegory%/%postname%/

Hi, I need to use this structure in my blog’s permalinks

/blog/%category%/%postname%/

It seams to work, but if I go to page 2 (for example http://wp.local/blog/mycategory/page/2/ ) it works wrong.

I see in my page “Uh Oh! Something terrible happened!”.

How can I solve this?