If redownloading does not work, try placing the install files into a 8.3 named directory, for example
c:\temp
and install from there. Sounds crazy, but I have a Windows XP Home system at my office which keeps having installer issues like what you describe. At home I don't get this problem, but I am on XP Pro and I don't run all the same stuff as I do at work. Anyway my fix for any program that does this is to simply move it to a folder that follows the 8 character naming convention with no spaces and/or special characters.
I've often wondered if this doesn't have somthing to do with how XP Home handles file security permissions under an NTFS partition compared to XP Pro. I have not really jumped into the problem though.