I am getting an error Could not load definitions from resource net/sf/antcontrib/antcontrib.properties. It could not be found.
when I am trying to ant build on
It would appear that you haven't installed the ant contrib jar into the correct lib directory. This can be difficult to do if you have several installations of ANT.
My suggestion is to install your ANT plugins into the "$HOME/.ant/lib" directory. You could go one step further and automate the process as follows: