Magento just announced on their official blog that they've created a patch to fix many of the issues users have experienced with Magento CE 1.4.1.0

You can download here from a thread they've started, dealing specifically with the issues in version 1.4.1.0

Magento CE 1.4.1.1 is currently being tested, and is expected for release sometime next week or so, so hold on tight! The new release should fix the errors of 1.4.1.0 addressed by the patch. Users will be able to upgrade to 1.4.1.1 with or without having first applied the patch.

For more information, see the thread.