Admin permissions messed up after upgrade to 2.5

I’m slowly realizing that something is messed up with the Admin account’s permissions after upgrading to WordPress 2.5

For example:
— I can’t delete a draft of a post. It just gives me an error message that says: WordPress failure notice. Are you sure you want to do this? Please try again.

Clicking “please try again” does nothing but take you back to the previous page. useless.

— If I try and delete a tag I get the exact same message (the useless error message)

— If I try and delete a subscriber user account I get the exact same useless error message.

It seems like the admin account that I use (the only admin account on this installation of WordPress) does not have the correct permissions to do all of these admin activities. This only started happening after upgrading to WordPress 2.5 so I imagine this means the permissions were messed up during the upgrade process.