I've tried to update 10.04.3 Server but I get an error (sorry but trey're written in slovene) says that cannot download updates and cannot connect to http://si.archive.ubuntu.com lucid Release
Could also be a temporary problem of slovenian mirror.
If persist (or if you hurry), try to replace with other repository.
Replace "http://si.archive.ubuntu.com" occurrences with http://archive.ubuntu.com/
Let me know