Forum Moderators: open
Use the site search and you'll find all that you need. Briefly, if this is a new site, then a white bar is perfectly normal. You'll need to wait for a couple of updates for PR to show, assuming the site has links by then.
If, as you seem to be saying, that the domain name has not changed but the contents have, then there are all sorts of other issues to read up on.
Everything is normal for a new site. Wait 2 or 3 months before things stabilise.
Please enjoy this tool WebmasterWorld Google Knowledgebase V2 [webmasterworld.com].
Then hit the library [webmasterworld.com], you will find plenty of info about this topic.
Enjoy!