Step 4 Problems

[Ning]

Hi to everyone here at the forum. I am trying to get an install of Prestashop working, but unfortunately am getting stuck on step 4. I get an error at the bottom of the page that reads:

Error while inserting data in the database:

(but no error is specified)

I get an email saying Prestashop is ready to run, but it doesn't seem to be... re-visiting index.php now shows just a blank page.

There is data in the database, so obviously Prestashop was able to write to it in earlier steps.

PHP 5.2.9 on CentOS 5.5

Please let me know if you need any other info.

I do realize similar questions have been asked, but have not really been resolved as far as I can tell.

Thanks in advance for any help you can offer.