Error 29506 while installing SQL Server Management Studio Express

I’m trying to install SQL Server Management Studio Express on my PC running Windows XP Professional (SP2). Every time I try running it fails with an error at the very end of the installation.It ends with an error “The installer has encountered an unexpected error installing this package.This may indicate a problem with this package.The error code is 29506”. I tried looking for a solution everywhere. Some suggested running the file (here its an .msi file) from the command prompt with Administrator privileges. I tried that and it is still giving the same error.