Hi all

I have just upgraded from 1.5.0 to 1.5.4 using the winmerge technique

The site seems to be working fine but when in the admin back end, if I go to (for example) Configuration>My Store>Store Name>Edit and then click the update button the url switches from ../configuration.php?gID=1&cID=1&action=edit to .../configuration.php?gID=1&cID=1&action=save .

Although the data is saved I am left with a blank page and have to hit the back button on the browser.

Any suggestions?

I have no idea where to start looking