When I opened GB for the first time, it asked for some download of around 1.5GB.
But due to sme network problems, my internet got disconnected and thus the download.
When I tried doing it again, it wasn't able to complete (actually start) and showed up a message.
"" GB was not able to complete the download.
Please refer to the Help secton of the Apple Store.
Click the "?" button to view more information. ""
I even tried removing the complete GB and installing it again bt it didn work.
Try mteep's manual download strategy:
Re: GarageBand '11 won't download additional loops
If that does not work, uninstall and trash the preferences, see Dagon's post:
Retrieving data ...