Unable to write entry is an issue with permissions. You'll need to ensure everything is writeable. This can be hard to debug but it should complain adequately.

Not sure why people aren't getting the file downloaded properly, appears to be an issue with FTP mode for some reason that I can't track down. It is on my todo list, but it is hard to replicate because it works fine for me. It is also a strange error.

For the no suitable wrapper error try using cURL instead to grab the file. Make sure you're on PHP5+ (preferably 5.2.0+ as this is the base line for my servers) which will give you the best chance of getting everything working fine.

Problem solved! I just have to check my server configuration and activate the fopen directive. I thought it was active by default but, for security reasons, my hosting got it disabled. Wise action BTW.

Thanks for your help!

Great to see that you got it worked out then!

Can't use fopen on my host, so I'll have to stay with manual updates for the moment.

Did you try using the curl option in the params?

Yes - my settings are cURL, 1.5 default, no proxy. I still get the checksum error. It's probably something on my hosting.