W
pierwszym wyniku z google jest wyjaśnienie.
Na moje oko najbardziej prawdopodobne jest:
"4. Insufficient disk space for temporary files
In some situations it may be that the installer's own free disk space check succeeds, but it then in fact ends up not having enough disk space on the drive or partition where temporary files are stored (usually C:\Documents and Settings\<my username>\Local Settings\Temp\).
In this case you should try to free up as much space as possible on the drive that contains the temporary files (usually C:) - 1GB is a recommended minimum, a few GB is advisable."