If you try a different theme do you still have the same problem? If not, contacting the theme author and asking for support is probably your best bet.

You could also try my Error Reporting plugin set to include the wp-contents folder. Then you may be able to spot the cause and fix it.

Thanks for the article…I have been having issue of blank screen for a while now…If I do not have any plugins on my wp 2.8 then it works…but if I enable some plugins like supercache, related posts the it starts giving blank pages for tag pages…Only Tag pages not categories nor single pages. I am using Thesis framework and have been unable to resolve this issue for last 3 months.
Please help