You failed to provide almost all information that is needed to help you:
- how are you trying to install the bootloader? Using Rockbox Utility (which has a known issue with the "Complete Install" in the current release which is *noted* on the appropriate page!) or using sansapatcher?
- do you have the correct permissions? Bootloader installation requires administrator permissions on windows
- are you running windows vista? Installing the bootloader on vista currently only works using the manual method using sansapatcher
I *guess* that you simply used the "Complete Install" button in Rockbox Utility and failed to read the "Issues" section on the page ... *sic*
And the tread title also doesn't follow our posting guidelines -- we require you to use descriptive topics, and "help" isn't descriptive at all.