Please help

[simoncn]

Do you get the unrecognised server error during the "Uploading" phase or during the "Installing" phase?

I would expect it to be happening during the "Uploading" phase. This means there is an issue with communication between the server and the browser you are using to do the upload. From a web search for this error, a few other people have seen this with other add-on packages. In some cases they could work around it by using a different browser.

Do you have another computer or another browser you could try? If you are using a wireless connection, could you try wired instead? Is anything else running on your computer that is taking a lot of CPU or memory and could interfere with the upload?