Tabs not visible on CiviCRM Contact record page

I have installed civicrm 3.0 alpha1 from svn with drupal 6.13

1. while browsing to civicrm contact record page, tabs are absent (i have attached the screen shot - contact_page.png)
2. also when clicking on the links on this page results into html page with white back ground (i have attached screen shot - event_page.png)
3. when i saw the error in firebug is shows following message :
" cj("#tab_tag a").text().trim is not a function
[Break on this error] if( cj('#tab_tag a').text().trim().slice(6,-1) == '0') { ".