I will give you the steps for fixing the pager manually but we don’t take responsibility for any inconvenience due to errors in any step from your side. The fix we provide is to redownload the theme which is working properly now.
Steps for fixing the pager:
1- Copy the file pager.phtml from app/design/frontend/base/default/template/page/html to app/design/frontend/default/[your_theme]/template/page/html
2- In the file catalog.xml in line 82 replace the #reference content with the following:
3- Erase the toolbar folder in app/design/frontend/default/hellosimple/template/catalog/product/list/
4- Copy the file: app/design/frontend/base/default/template/catalog/product/list/toolbar.phtml in app/design/frontend/default/hellosimple/template/catalog/product/list/