Don't take everything you see on a site as 100% truth.
The information held is only accurate upto the latest return of the person
or company concerned.
Are you checking 'is the builder ok?' in a money way or a quality of work way?
If the contractor operates as a limited company you can obtain information on their last accounts at [broken link removed]
If they are a sole trader etc., its very difficult to be sure.
You could ask for a reference from their Bank Manager perhaps, or ask around to see who they do business with (the local builders suppliers may be useful if you know someone working there).
If you need advice on the financial status of a company, you are probably better to move this post to another section of the site.