Failed to prepare partial IU: [R]com.googlecode.veloeclipse.ui 2.0.8.

work around:

go to Help -> Install New Software..., choose "The Eclipse Project Updates - http://download.eclipse.org/eclipse/updates/4.4" from the "Work with" list and then in the "Eclipse Tests, Examples, and Extras" category check "Eclipse 2.0 Style Plugin Support" and install it. After restarting Eclipse, install veloeclipse again and this time the installation will succeed.