Here's the meaning of the error message:
0x8024200D -2145116147 SUS_E_UH_NEEDANOTHERDOWNLOAD The installer requires more data to be downloaded
Are you fully updated (with the exception of SP1)?
If so, there's 3 things to do:
1 - scan your system to be sure there's no infection present
2 - ensure that all of your drivers are compatible with SP1
3 - Download and install the standalone installer for SP1 from here (make sure you get the correct version - the wrong one won't install):
The first two steps are the major reasons that service packs fail to install - and most issues are fixed by that.
In the event that the first 2 solutions don't work, the next step is always the standalone package - as it removed Windows Update from the process (which is one less thing that could go wrong).