updating WordPress to 2.9.2

I cannot upgrade to 2.9.2 I keep getting message that it was unsuccessful and to try again. I have tried 10 times. Unpacking is as far as the process gets. I called my hosting company – they don’t help with WordPress – even though they claim to be a perfect partner with the them. I have deactivated plug ins and read all the forum answers I can, but most of the answers are beyond me – like manually updating. What are my options – what else can I try? I don’t want to be hacked!