Post problems with 3.1.1

I’m having very strange issues with 3.1.1, i’ve searched the forums and found a lot of people reporting similar problems.

I am working with a fresh WP install (I have reinstalled at least 5 times and downloaded the package at least 3 different times both in zip and tar.gz, so please rule out the possibility of corrupted files). There are no plugins, and the only theme is Twenty Ten. It is running on an Apache server, all permissions are set to 750 except the wp-content folder which is 770. I have rolled back to 3.0.5 now, and everything is fine, so it has to be a specific problem with 3.1.1.

The problems all relate to the post section on the admin panel:

1) When creating/editing a post, a lot of the features that were in previous versions i.e. ability to write an exerpt, send trackbacks, add custom field – all missing in my installation (basically there is nothing below the visual editor).

2) Cannot insert images into a post – the “add an image” dialogue box does not function properly. I can select a file and it seems to upload, but it does not give any response after I select the file to upload. Also, nothing is selectable in the ‘Gallery’ section.

3) Strangely, the visual editor displays text in white, making it invisible as the visEd background is also white. I found that the text color was explicitly set to white in the CSS, really strange!

I have heard that 3.1.1 is actually not stable. Might be wrong but these are really wierd problems with 3.1.1 that I have never had with any WP installation.

I don’t mind sticking with 3.0.5, but does anyone know if there are any major security vulnerabilites that 3.1.1 has patched up?