Admin Pages Return Blank (White) Screen Unless I Click on the URL

Hello,

Whenever I submit any type of administrative change, such as saving a new block, I get a white screen. If I click on the URL at the top of the browser, the command executes and everything works, but I don't want to have to do this manually every time.

The rest of my site loads just fine--no white screens. Seems the problem is confined to admin tasks.

Thanks very much for any advice!