Well this is my first wordpress upgrade that things haven’t gone completely smoothly 
It had to happen sometime.
I installed a clean new version of wordpress to identify if the issue was my blog or if it was the server.
I initially had two errors when upgrading.
The first was 3 javascript errors that occured everytime I pressed an icon that opened a window in the visual editor. Eg the image button or the link icon. This didn’t happen on the new install and so with a few clears of the cache and it is now working.
The second error is in the uploader and unfortunately this happens with the clean install. I get the message: “An error occurred in the upload. Please try again later.” I have the flash debug player installed and it gives me the error that there was an unhandled IO exception.
I have checked folder permissions on the folders and they are correct. I don’t have the absolute latest flash player as the debug version isn’t the latest. However I can’t think of a reason it would need the absolute latest flash player to work. After going through all the options in the stickied support post, I ended up having to install the plugin to disable the flash uploader.