It sounds to me as if there are dependancy issues that are not being resolved.  The error message is suggesting that you update the package listing using apt-get update.  So run the command sudo apt-get update to refresh the package database, then run sudo apt-get install ubuntu-desktop to see if the dependency issue has cleared up.  If the missing packages get downloaded, then you are home free.  If there are still errors, then either the repository you are using is missing packages, or you don't have all the necessary repositories to resolve the issue.  I suppose if you know what packages are missing you can try to search for which repository contains said packages, and try to add them to your /etc/apt/sources.list file.  Let us know if this resolves your problem.

yeah you may have to comment out the repos that you are getting errors from.  the unofficial ones.  then run the sudo apt-get update again and all should be ok.

Thanks bro with your support.  I'm continue the download process with this command " sudo apt-get install ubuntu-desktop " then i press enter button. So system are continue download and install the package. But by the end i got this error =>  http://www.loadmyimg.com/viewer.php?file=rm6vsmgvnvzg71p9oe12.jpg So.. how to i continue installing ubuntu-desktop on Ubuntu Server 8.0.4

After i got that error (above), i use command " sudo apt-get update ". i got this error => http://www.loadmyimg.com/viewer.php?file=vbhl8autnddo55583deu.jpg I use command suggested by system, " sudo dpkg --configure -a ". Again.. i got this error => http://www.loadmyimg.com/viewer.php?file=w6ukvu126fwg6yl1kz0d.jpg So.. what should i do next..??

Well alkev, I'm a bit at a disadvantage because it appears you are installing Hardy under VMWare with a Windows XP host.  The only virtualization I have experience with is installing Win98 under Win4Lin and WinXP under VirtualBox with a Linux host.  The first error messages where dpkg is complaining about a "read-only" filesystem is certainly a problem.  Are you sure that VMWare is properly configured?  Does your bottle have enough space allocated?  Is your hard drive full?  There is some kind of problem that is causing Ubuntu to fail its installation in "oh so many ways".  This failure is probably the cause for all your other errors.  I guess you really need someone who has experience installing Hardy under a WinXP host and VMWare.  I would go back to my VMWare configuration and make sure that is not your real problem.  Sorry I can't give you more advice, but I am pretty much out of familiar territory with VMWare.               And you might need to reconfigure your /etc/apt/sources.list file to specify a different mirror.  I'm guessing there has been some change in the hardy-updates repository.