My b2evolution Version: Not Entered

Hi
As I am new to Blogs I installed B2 on my windows server with MySQL and PHP5 after completion of the setup process I get the following error when I try to open my blog or the admin page:

Fatal error: require_once() [function.require]: Failed opening required 'E:/domains/w/whysir.co.uk/user/htdocs/blogs/inc/generic/model/_genericcache.class.php' (include_path='.;C:\php5\pear') in E:\domains\w\whysir.co.uk\user\htdocs\blogs\inc\_core\_class4.funcs.php on line 40

When I open the Class4 file it states that another page is required to run PHP5

Where can I get this file?

Jim Owens